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pMJFORNI/^
FISH- GAME

"CONSERVATION OF WILDLIFE THROUGH EDUCATION"

I VOLUME 61

OCTOBER 1975

NUMBER 4 J

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California Fish and Game is a journal devoted to the conservation of wild-
life. If Its contents are reproduced elsev/here, the authors and the California
Department of Fish and Game v/ould appreciate being acknov«^ledged.

Subscriptions may be obtained at the rate of $5 per year by placing an
order with the California Department of Fish and Game, 1416 Ninth Street,
Sacramento, California 95814. Money orders and checks should be made out
to California Department of Fish and Game. Inquiries regarding paid sub-
scriptions should be directed to the Editor.

Complimentary subscriptions are granted, on a limited basis, to libraries,
scientific and educational institutions, conservation agencies, and on exchange.
Complimentary subscriptions must be renewed annually by returning the post-
card enclosed with each October issue.

Please direct correspondence to:

Robson A. Collins, Editor
California Fish and Game
350 Golden Shore
Long Beach, California 90802

VOLUME 61

OCTOBER 1975

NUMBER 4

Published Quarierly by

STATE OF CALIFORNIA

THE RESOURCES AGENCY

DEPARTMENT OF FISH AND GAME

—LDA—

STATE OF CALIFORNIA

EDMUND G. BROWN JR., Governor

THE RESOURCES AGENCY

CLAIRE T. DEDRICK, Secretary for Resources

FISH AND GAME COMMISSION

TIMOTHY M. DOHENY, President, Los Angeles

JOSEPH RUSS III, Vice President PETER T. FLETCHER, Member

Ferndale Rancho Santa Fe

BERGER C. BENSON, Member SHERMAN CHICKERING, Member

San Mateo San Francisco

DEPARTMENT OF FISH AND GAME

E. C. FULLERTON, D.Vecfor

1416 9th Street
Sacramento 95814

CALIFORNIA FISH AND GAME
Editorial Staff

ROBSON A. COLLINS, Editor-in-Chief Long Beach

KENNETH A. HASHAGEN, Editor for Inland Fisheries. Sacramento

CAROL M. FERREL, Editor for Wildlife . _.Sacramento

ROBERT N. TASTO, Editor for Marine Resources . . Menio Pork

PAUL M. HUBBELL, Editor for Salmon and Steelhead Sacramento

HAROLD K. CHADWICK, Editor for Striped Bass, Sturgeon, and Shad Stockton

(1&4)

CONTENTS

Page

*o'

Breeding Status of the Tricolored Blackbird, 1969-1972
Richard W. Dellaven, Frederick T. Crasc and Paul P. Woronecki 166

The Age and Growth of the Pacific Bonito, Sarda chilicnsis, in the
Eastern North Pacific Gail Campbell and Robson A. Collins 181

Parasites of Fishes from the Sacramento-San Joaquin Delta, Cali-
fornia Gary H. Hensley and F. M. Nahhas 201

Fish Trapping : A New Method of Evaluating Fish Species Com-,
position in Limnetic Areas of Reservoirs

Larry J. Paulson and F. A. Espinosa, Jr. 209

Aspects of the Life History of Trcsus nuttalli in Elkhorn Slough

Patrick Clark, James Nybakken and Lawrence Laurent 215

Notes

Notes on the External Parasites of California Inshore Sharks

Ronald A. Russo 228

An Extrauterine Fetus in the Steller Sea Lion, Eumetopias
jiibata Larry G. Talent and Carline L. Talent 233

Anomalous Otoliths from the Northern Anchovy, Engraulis
mordax Jerome D. Spratt 235

The Stewart Modified Corral Trap

Ronald D. Rempel and Ronald C. Bertram 237

The Status of Rocky Mountain Elk in Kern County, 1974

Ronald D. Thomas 239

Modification of the Clover Deer Trap Dale R. McCullough 242

Blood and Serum Analysis of Adult Striped Bass Captured in
the Sacramento River Louis A. Courtois 245

Measuring Salmon, an Old and Unfamiliar Method

Donald H. Fry, Jr. 247

Further Record of the Little Kern Golden Trout, Salmo agna-
bonita whitcri, in the Little Kern River Basin, California

J. R. Gold and G. A. E. Gall 248

Poeciliopsis gracilis (Heckel), Newly Introduced Poeciliid Fish
in California Alan J. Mearns 251

Polymorphism in Populations of Sceloporus occidcntalis in Santa
Barbara County, California Robert L. White 253

Book Reviews 255

Index to Volume 61 263

(165)

Calif. Fish and Game 61(4) : lGG-180. 1075.

BREEDING STATUS OF THE TRICOLORED BLACKBIRD,

1969-1972^

RICHARD W. DEHAVEN, FREDERICK T. CRASE

and

PAUL P. WORONECKI ^

U.S. Fish and Wildlife Service, Denver Wildlife Research Center Field Station,
Box C, Davis, California, 95616

During 1969—1972, 164 breeding colonies of tricolored blackbirds were
found in California and southern Oregon. The location of the colonies,
their sizes (including acreage, number of birds, and number of nests),
and nesting habitats are given and comparisons made with previously
reported data. The tricolor's general range and major breeding areas
have remained unchanged during the past 35 years, but in the Central
Valley, population size has declined, perhaps by more than 50%. Possi-
ble causes for the decline are given, and other aspects of the tricolor's
breeding ecology are discussed.

INTRODUCTION

Since 1967 Ave have studied blackbird damage to rice in California.
Our first step in defininfr tliis problem was to investigate the population
status of the various species involved in depredations, -with particular
emphasis on the tricolored blackbird (Aqelaius tricolor) because of its
enclemic distribution. Neff's (1937; 1942) studies provide the basis for
much current knowledge about the tricolor, but because his data were
gatliered more than 30 rears ago and because more recent workers
(Orians 1961a, 1961& ; Orians and Collier 1963; Payne 1965; and Collier
1968) have not provided data on the tricolor's general distribution and
numbers, its present status was uncertain. We therefore studied the
tricolor during four breeding seasons during 1969-1972. This paper
presents our findings on the size and distribution of the tricolor breed-
ing population, and compares them with earlier findings.

METHODS

Each spring (April-June) different portions of the tricolor's range
were surveyed by auto for breeding colonies. In 1969 and 1970, the
survey was concentrated in the Central Valley (combined Sacramento
Valley: Tehama, Butte, Gleini, Colusa, Sutter, Yuba, Yolo, Solano, and
Sacramento counties; and San Joaquin Valley: N"\V Kern, Kings, Tu-
lare, Fresno, ]\Iadeia, Merced, Stanislaus, and San Joaquin counties). In
1971 we attempted to survey the entire breeding range (excluding
Baja California) by driving more than 8,000 miles and visiting most
of the reported breeding areas (Table 1) from San Diego through
southern Oregon. Iii 1972 our search was conducted from the northern
San Joaquin Valley through southern Oregon. Some of the tabular
data also include four colonies we found during brief explorations in

' Accepted for publication Xoveinber 1974.

= Present address: Patu.xent Wildlife Research Center Field Station, Box 2097, San-
dusky, Ohio 44780.

(166)

TRICOLORED BLACKBIRD BREEDING STATUS

167

• Breeding colony

■^Flock seen during
breeding season
but no colony
found

SAN lOAQUlN
V.ALLEY

FIGURE 1. Location of tricolored blackbird breeding colonies 1968-1972. (Some of the
locations represent more than one colony.)

168 CALIFORNIA FISH AND GAME

the Sacramento Valley in 1968. Durin<if each of the survey years, records
of several additional colonies were provided by amateur and profes-
sional ornithologists. However, becaiLse we could not thoroughly investi-
gate Jill colonies and because many of our cooperators' reports were
incomplete, all data are not available for each colony.

Estimates of different population segments were made by counts and
by projections based on the findings of Payne (1965), Lack and Emlen
(1939), and Lack (1968) who indicated that each tricolor female attends
only one active nest and that the male : female ratio averages about
1 : 2. If a colony was located early in the nesting cycle when both males
and females were present, the breeding population was directly esti-
mated by counts, and the number of active nests to be built was
projected. During later nesting stages, such as incubation when the
males are absent, or the nestling stage when both sexes may be away
from the colony in search of food, the nests were counted and the
breeding population wa.s projected.

DISTRIBUTION OF COLONIES
Geographic

Including the four colonies in 1968, we found 168 breeding colonies
at 113 locations, each at least 1.6 km (1 mile) apart (Table 1; Figure
1). About 78% (131) of the colonies were in the Central Valley, with
48 7o (80) in Sacramento Valley, and 30% (51) in the San Joaquin
Valley. The remaining 22% (37) were in other parts of California and
in southern Oregon. The counties (all in the Central Valley) where
the most colonies were found in a single season were Sacramento (11),
Merced (10), Stanislaus (7), Glenn (7), and Colusa (4).

Neff (1933; 1937) reported tricolor colonies in 26 counties in Cali-
fornia and one county in Oregon ; but he believed occasional breeding
was likely in at least 15 additional counties. Later, breeding records
were published for five more counties in California (Lassen, Alameda,
Santa Clara, Ventura, and Riverside) and one in Oregon (Jackson)
(Table 1). And in our survey, we found tricolors breeding in four
additional counties in California: Sonoma (near Petaluma), El Dorado
(near Salmon Falls Road), Modoc (at Clear Lake National Wildlife
Refuge), and Siskiyou (at Lower Klamath and Tule Lake National
Wildlife Refuges) (Table 1 ; Figure 1).

We did not find tricolors breeding in four California counties
(Marin, Solano, Santa Cruz, and Fresno) where Neff (1937) reported
them, but this does not necessarily mean that breeding has declined in
these areas. The colonies he found were relatively small (6 to 500 nests),
and our searches were limited to one or two quick drives through each
county by road.

TRICOLORED BLACKBIRD BREEDING STATUS

169

TABLE 1. Number and Size of Tricolored Blackbird Breeding Colonies Reported
Since 1933 and Found During 1968-1972, by Year and County

County

Butte.

Glenn.

Tehama.

Year(s)

Colonies (range during years)

Number

Size

Sacramento Valley, California

Sacramento
Yolo

Placer

Sutter

Lake

Colusa

El Dorado.
Yuba

32-3C

1-3

69-72

6-11

31-36

1-3

69-72

33,36

32-36

1-3

32-34, 36

2-11

59*

59-60

3-4

61*

69-72

1-4

31-36

2-9

59*

59-60

2-3

62-63

60-64*

1-2*

69-70

1-2

32-36

2-13

61, 64*

69-72

1-3

32-36

3-7

63*

63-64

69-72

1-3

72*

69-70. 72

1,000-121,000

30,500

15,850- 50,915

2,000- 38,000

2,000

70,000

31,000

1,500

5,000-

1,000-

13,000

25,000

2,500

3,000- 37,000

19,500

104,650-156,500

4,000

1,000- 57,000

800

2,000-113,000

60,000+

22,000

2,150

17,300- 55,000

100- 400

1,000- 5,250

3,000-106,000

35,000

100- 150

500- 25,000

4,000-282,000

2,000- 18,500

1,000

1,500- 2,000

nests
nests
birds
nests
birds
nests
birds
nests

nests
birds
nests
birds
nests
nests
nests
nests

birds
birds
nests
birds
nests
nests
nests

nests
birds
nests
nests
nests
birds
nests
nests

birds
nests
nests
birds

San Joaquin
Stanislaus. .

Merced

Fresno

Kings

Tulare

Kern

35-36

1-4

69-72

1-2

32, 35-

-36

2-6

69-72

2-7

32-36

1-19

69-72

3-10

62, 64

63*

35-36

1-2

56, 58-

1-2

71-72

San Joaquin Valley, California

100-

500-

8,000-

4,200-

2,000-

12,500-

500-

200-
?

2,000-

3,750
5,050
12,500
25,300
58,000
26,000
100
10,000

101
2,000
25,000
2,000
1,500
2,000
1,000
2,000

600
3,000

nests
birds
nests
birds
nests
birds
nests
birds

nests
nests
birds
nests
birds
nests
nests
nests

birds
birds

Source

Neff 1937

Orians 1961a

Present study

Neff 1937

Lack and Enilen 1939

Orians 1961a

Present study

Neff 1937

Present study

Neff 1937

Present study

Neff 1937

Present study

Neff 1937

Orians 1960

Orians 1961a

Payne 1965

Present study

Neff 1937

Lack and Emlen 1939

Emlen 1941

Orians 1960

Orians 1961a

Payne 1965

Present study

Neff 1937

Orians 1961a

Payne 1965

Present study

Neff 1937

Payne 1965

Present study

Neff 1937

Present study

Neff 1937

Present study

Neff 1937

Present study

Neff 1937

Present study

Neff 1937

AFNt 10(4): 362, 1956

Payne 1965

Neff 1937

Present study

Neff 1937

Present study

Neff 1937

AFN7(4):292, 1953

Collier 1968

Orians 1961a

AFN 13(4): 402, 1959

Present study

170

CALIFORNIA FISH AND GAME

TABLE 1. Number and Size of Tricolored Blackbird Breeding Colonies Reported
Since 1933 and Found During 1968—1972, by Year and County — Continued

County

Year(8)

Colonies (range during years)

Number

Size

Source

Northern California — southern Oregon

Shasta (Ca.)--

Lassen (Ca.)-.
Modoc (Ca.)--
Siskiyou (Ca.)
Klamath (Or.)

Jackson (Or.).

32-33

70-71

09-72

2-4

-3

1,000-

12.5-
2.50-

18,000
.5,000

2,50

10,200

180

1,000

1,800

100^

nests
birds

birds
birds
nests
nests
nests
birds
birds
birds

NefT 1937
Present study
AFN 10(4): 445,
Present study
Present study
Neff 1933
Present study
AFN 12(4) :379,
Richardson 1901
AFN 17(.5):479, 1903
AFN 19(5):. 573, 1905
Present study

1902

19.58

Marin

Sonoma

Solano

Alameda

Santa Clara. .

Santa Cruz

Monterey

Santa Barbara

Ventura

Los Angeles

Riverside

Orange

San Diego

32, 30

.57-59

.59-00

43. 51

69-71

32. 3.5-30

70-72

Coastal and southern California

?
150-

1-3

2-3

-3
-4

2,000-

17.5

300-

5,000-

100-

7
5,000-

NefT 1937

3,000

birds

Present study

nests

NefT 1937

4.000

birds

AFN 20(4):. 545

1900

11,200

birds

Present study

AFN 5(4): 270.

1951

500

nests

Neff 1937

4,000

nests

Neff 1937

400

birds

AFN 13(4): 398

19.59

5.000

birds

Present study

3,000

nests

Neff 1937

1,200

birds

Present study

1,800

nests

Collier 1908

500

nests

NefT 1937

COO

nests

Collier 1908

2,.500

birds

Present studv

2,000

birds

AFN 5(5): 309,

1951

15,7.50

birds

Present study

2.50

nests

Neff 1937

3,000

nests

Neff 1937

2,000

birds

AFN 10(4) :448
Payne 1905

1962

9.000

birds

Present study

* Fall breeding colonies.

t AFN = Audubon Field Notes.

In several other areas, we saw flocks of tricolors diiriiifr the breeding
season without findinj; colonies (Fijjure 1). At Honey Lake (Lassen
County), for example, about 20 niah^s wei-e seen sin<Tin<r in a tree. About
60 tricolors Avere si<^hted in a field near Yrcka (Siskiyou County), and
flocks of 100 to about 1,000 were seen near Cliula Vista and near Otay
Reservoir (San Diejro County) ; near Los Alamos (Santa P>arbara
County) ; near Reddin<r (Sliasta County) ; near Moss Landinfr and on
Hunter Ligrgett Military Keservation (Monterey County) ; and in tlie
San Benito River Valley (San Benito County). Published records
(Table 1) report tricolor breeding in all of these counties except San
Benito.

TRICOLORED BLACKBIRD BREEDING STATUS 171

Geographically, the breeding range of the tricolor has changed little
during the past 30 years. Colonies are still found from southern Ore-
gon south through Shasta County, California, and along the coast of
California from Sonoma County to the Baja California border.
Sporadic breeding also occurs in the plateau region of northeastern
California and in the northwestern extremity of the Mojave Desert, but
by far the majority of tricolors still breed within the Central Valley.

General Habitat

Within the Central Valley, breeding colonies were generally found
in two major agricultural types — the rice lands of the Sacramento Val-
ley and the pasturelands of the lower Sacramento Valley and San
Joaquin Valley. In the rice lands, the annually flooded rice is the domi-
nant crop, but small grains, hay, safflower, sugar beets, corn and beans
are also grown. The pasturelands consist largely of irrigated tields of
introduced grasses, alfalfa (grown for seed), hay, and small grains. In
both areas, insects in flooded fields probably provide the primary food
for breeding tricolors (Crase and DeHaven, manuscript in prep.).

Colonies outside the Central Valley were in several different habitat
types. For example, at East Park Eeservoir (Colusa County) and near
Alberhill (Riverside County), breeding areas were surrounded by
chaparral covered hills extending for several miles in all directions. A
colony near Fallbrook (San Diego County) was surrounded by several
hundred acres of orange and avocado groves interspersed with grass-
covered hills a few acres in size. Two colonies in Alameda County were
adjacent to the salt-marsh habitat of San Francisco Bay. At Clear
Lake National Wildlife Refuge and at the Lava Beds National Monu-
ment (Siskiyou County) colonies were in sagebrush-grasslands.

Two southern California colonies probably best illustrate the tricolor's
ability to breed under widely varying environmental conditions. A
colony of about 2,500 adults was nesting in a small agricultural area
near Del Sur (Los Angeles County), which is on the western edge of
the Mojave Desert, and a group of several small colonies was found
within the city limits of Santa Barbara (Santa Barbara County), about
274 m (300 yards) from the Pacific Ocean. Of the two sites, the desert
breeding is probably more unusual, since the tricolor has apparently
not invaded the man-made agricultural environment in the desert of
the Coachella Valley (Riverside County), although less than 121 km
(75 miles) of semi-desert separates the area from other breeding sites.

Nesting Substrate
The vegetation in which nests were built was recorded for 156 colonies
(Table 2). Of these, 108(69%) had nests built in some kind of marsh
vegetation — cattails {Typha sp.), bulrushes (Scirpus sp.), willows (Sa-
lix sp.), or some combination of these, and 76 (49%) were in cattails
only. Other workers have also reported marsh vegetation as the major
nesting substrate. In particular, of 256 colonies Neff (1937) found, 246
(96%) were in cattails, willows, and bulrushes. Orians (1961a) re-
ported that 16 (64%) of the 25 colonies in the Sacramento Valley were
in cattails and other emergents. And Collier (1968) found 27 (84%)
of 32 southern California colonies in marshes or riparian willows.

172

CALIFOKXIA FISH AND GAME

The size, configuration, and ])]ant density of the marshes used for
nestiufr -were extremely variable. Near Red Bluff (Tehama County),
a l,r)()()-bird eolony nested for 2 eonsecutive years in a burned-over
eattail marsh -where the vegetation Avas less than 0.9 m (8 ft) tall and
nearly too sparse to support the nests (which were often only a few
inches above the water) ; near Modesto (Stanislaus County) a colony
of more than 1,UU0 birds nested in a strip of cattails only 3 m (10 ft)
wide and 22.9 m (75 ft) long; near Arbuckle (Colusa County) adults
nested in 3.7 m (12 ft) tall bulrush and eattail that was too thick for
a man on foot to penetrate. In general, we observed no preference for
a particular shape of marsh such as the broad circles or irregular
polygons that Collier (1968) thought tricolors preferred.

"We also found tricolors nesting in blackberry {Ruhus sp.), mustard
(Brassica campcsfris), thistle {Ccnfaurca sp.), nettle (Vrtica sp.), saf-
flower (Carihamus iinctorius), and giant reed {Ariindo donax) (Table

TABLE 2. Number of Tricolored Blackbird Breeding Colonies by
Nesting Substrate, 1968-1972

Number of breeding colonies found

Nesting substratP

1968

19C9

1970

1971

1972

Total (%)

Cattail

13
2

1
1

20
7

4
1
1

1
1

28
8

11
3

3
2
2

1
2

13
5
4

1
1

70 (48.7)

Cattail, bulrush _ ._ _.

23 (14.7)

Blackberries .

2.5 (10.0)

WDIows - -.-

0 (3.2)

Bulrush - -

7 (4.5)

Mustard, thistle

5 (3.2)

Thistle -

2 (1.3)

Giant reed

3 (1.9)

Mustard

3 (1.9)

Nettles

2 (1.3)

Cattail, bulrush, willows

2 (1.3)

Mustard, safflower.

1 (0.0)

Nettles, willows, blackberries

2 (1.3)

Total - _

150 (99.9)

2). We know of no previous report of nesting in giant reed, although
tricolors nested in this at least three times during our study (near
Manteca, San Joaquin County, where 3,000 birds nested in 1971 and
1972, and near Del Sur where the 2,500-bird colony mentioned earlier
nested near the desert).

Altitudinal Dispersion

Neff (1937) found colonies from sea level near San Diego and Santa
Cruz to about 1.280 m (4,200 ft) on Klamath Lake. More recently.
Collier (1968) reported a colonv near Tehachapi (Kern County) at
1,158 m (3,800 ft) and Audubon' Field Notes (16: 445, 1962) reported
a colony near Susanville (Lassen County) at slightly over 1,219 m
(4,000 ft). We found a similar altitudinal dispersion, with colonies
ranging from sea level in Santa Barbara and near Alameda (Alameda

TRICOLORED BLACKBIRD BREEDING STATUS

173

County) to 1,362 m (4,469 ft) at Clear Lake National Wildlife Refuge.
However, altitudes in the Central Valley, where most colonies are lo-
cated, are only about 6.1 to 121.9 m (20 to 400 ft) and those in the high-
density tricolor breeding areas in Merced, Stanislaus and Sacramento
counties (Figure 1) are only about 18.3 to 30.5 m (60 to 100 ft).

Fall Breeding

Although we were aware of possible fall breeding by tricolors in the
Sacramento Valley (Orians 1960; Payne 1965), and in fact searched
for colonies several times, we found only one instance of fall breeding.
This was a colony of about 1,000 nests apparently all unsuccessful, in
a cattail pond on the Sacramento National AVildlife Refuge (Glenn
County) during November 1972. We do not know if fall breeding
occurred in other parts of the species' range.

SIZE OF COLONIES

Numbers of Birds

We estimated the number of breeding birds at 157 colonies (Table 3).
Of these, about 25% had fewer than 1,000 birds, about 627o had from
1,000 to 10,000 birds, and 13% had more than 10,000 birds.

TABLE 3. Number of Tricolored Blackbird Breeding Colonies by
Size Classes, 1968-1972

Year

Size class (number of breeding birds)

1968

1969

1970

1971

1972

Total (%)

Fewer than 1,000 . -.

2
2

11
25

20
36

40 (25.5)

1,000 to 9,999

97 (61.8)

10,000 to 25,000

19 (12.1)

More than 25.000

1 (0.6)

Total

157 (100.0)

The smallest colony, 15 birds, was observed in 1971 near Folsom
(Sacramento County). All large colonies were in the Central Valley.
The largest, about 30,000 birds, was observed in 1972 near Knights
Landing (Yolo County). Others, each containing about 20,000-25,000
birds, were: near Tudor (Sutter County) in 1968; near Colusa in 1969
and 1971 and near Dunnigan in 1969 (Colusa County) ; near Clay and
near Gait in 1971 (Sacramento County) ; near Corcoran (Kings
County) in 1971 ; and near Knights Landing in 1969.

The colonies outside the Central Valley all contained fewer than
10,000 tricolors. West of the valley, for example, the three largest
colonies were in the San Francisco Bay area (Alameda County), and
each had about 5,000 breeding birds. North of the valley, the largest
colony had about 1,250 birds at Tule Lake National Wildlife Refuge.

174

CALIFOKXIA FISH AND GAME

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TRICOLORED BLACKBIRD BREEDING STATUS 175

(About 10,000 tricolors were reported there early in the spring of 1969,
but the birds apparently did not all nest in one colony.) South of the
valley, the larg'est colony was about 2,500 birds in San Diego County.
A cooperator reported that a colony of about 10,000 birds nested near
Temecula (Riverside County), but we did not confirm this estimate.

Nesting Area and Density

The number of birds or nests and the area they occupied were esti-
mated for 109 colonies (Table 4). Nesting areas varied widely with the
size of the colony and the type and size of the local nesting substrate,
but generally nests were built in only a fraction of the total area
available. Also, areas occupied by more or less continuous nesting were
smaller in upland habitats than in marshes. Continuous nesting areas in
blackberries averaged .17 ha (0.41 acre) ; in all other upland types
they averaged .33 ha (0.82 acre). In contrast, nesting areas in marshes
averaged .65 ha (1.62 acres). In several marshes, nesting was nearly
continuous on at least 1.6 ha (4 acres) of the available habitat. The
largest areas of continuous nesting recorded w^ere on about 4.1 ha (10
acres) of mustard and thistle in Alameda County where 5,000 birds
nested, and on 10 acres of cattails (part of a 10.1 ha (25-acre) marsh)
in Colusa County where more than 20,000 birds nested.

The greatest nesting density was at the Del Sur colony, where 2,500
tricolors built nests in an area of giant reed only about 12.8 x 3.9 m
(42 X 13 ft) (1/80 acre) ; this is equivalent to about 200,000 birds, or
133,340 nests, per acre. Two sites with extremely sparse nesting den-
sities were a 15-bird colony at Folsom (in blackberries), and a 50-bird
colony at Tule Lake National Wildlife Refuge (in mustard and thistle),
where densities were only about 750 birds per acre. Overall, nesting
was densest in giant reed and blackberries; intermediate in mustard,
mustard-thistle, and willow ; and sparsest in cattails, bulrush, and com-
binations of these (Table 4).

POPULATION SHIFTS
Seasonal

Colony abandonment provided evidence of population shifts during
the nesting seasons. During the survey, we made repeated visits to
about one-third of all the colonies found, and of these, about 10% to
50% were partially or completely abandoned each year. The observed
abandonment occurred throughout each nesting season, although, like
Neff (1937), w^e observed it more often early in the year. In April
1970, for instance, we found about 10,000 tricolors at four breeding
colonies in southeastern Sacramento County. The birds were building
nests or incubating eggs. Within a few days, all four had been aban-
doned, and there was no later breeding in the area that year. Abandon-
ment likely is related to insufficient food supplies for the breeding
birds and their young (Lack 1954; Orians 1960, 1961rt).

Yearly
We also observed substantial yearly variation in the centers of breed-
ing abundance. In several counties in the Central Valley where man-
days spent searching was fairly constant each year from 1969 through

176 CALIFORNIA FISH AXD GAME

1972, the number of colonies and breeding birds usually differed
greatly between years (Tables 1 and 5). For example, in 1969 at least
57,000 tricolors nested in Colusa County, but in 1970 there were only
about 2,000. Similar fluctuations occurred elswhere in the Central
Valley.

Neff (1937), Orians (196U), and Orians and Collier (1963) also
reported that the breeding distribution of tlic tricolor was somewhat
unpredictable from year to year. Orians (I960; 1961fl), however, stated
that the tricolor's center of breeding abundance and the largest colo-
nies were in the rice-growing area of the Sacramento Valley. Our data
show that this is not true for all years. Only 5 of the 10 largest colo-
nies of our study were in the major rice district. Furthermore, in 1969
and 1972 about SS^r and 59% of all tlie breeding tricolors were in five
major rice-growing counties, but in 1970 and 1971 only about 32% and
29% were (Table 5). In 1971 we found only 49,000 tricolors nesting
in the five major rice counties, compared to the largest breeding popula-
tion (about 51,000 birds) which nested within a few square miles in
the pasturelands of southeastern Sacramento County.

These yearly shifts, which are likely related to insect supplies and
other, unknown, breeding requirements, may operate as follows : During
winter, many tricolors leave the Sacramento Valley rice areas. Probable
major wintering areas are the San Francisco Bay-Delta area and the
northern San Joaquin Valley (Neff 1937, 1942; Orians 1961rt; Payne
1965; and DeHaven et al.. manuscript in prep.). When spring arrives,
tricolors disperse from these wintering areas to search out sites with the
proper requirements for breeding, of which an abundance of insects is
probably most critical (Orians 1961fl; Orians and Collier 1963; Payne
1965; and Lack 1954). Movement is probably mainly northward from
wintering locations because areas with acceptable nesting substrates are
relatively scarce in the arid southern San Joaquin Valley.

Although population shifts occurred each year, there Avere a few
local areas, such as the pasturelands in Merced County near Gustine
and Los Banos and in Stanislaus County along the San Joaquin River,
where breeding was somewhat regular and predictable. Neff (1937)
also found regular breeding in the Merced County area which, judging
from his descriptions, seems to have changed little. However, })robably
the most consistently used area during our study was the pasturelands
in southern Sacramento County, where we found 6, 8, 11, and 4 colonies
during the years 1969-1972.

A few specific breeding sites outside of the Central Valley were
regularly used. A cooperator reported that near Temecula a colony was
active during 1!)67-1971. Colonies at Tule Lake and Lower Klamath
National Wildlife Refuges were active during all years of the study.
A land owner reported that one of the colonies we found near Santa
Barbara had been active for at least 25 years, and according to Bent
(1965), Nuttall first described the species from this or a nearby area
in 1836, and listed it as common in April.

TRICOLORED BLACKBIRD BREEDING STATUS

177

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178 CALIFORNIA FISH AND GAME

LONG-TERM POPULATION CHANGES

The findings of our survey were similar in niany respects to those of
Neff (1937) who first studied tricolor populations some 35 years earlier.
There were, however, several striking differences:

1) We found fewer colonies than Neff (1937). During G years of
study (1931-1936), he devoted an average of about 31 man-days a
year to specific searches for tricolor colonies, and listed a total of
more than 256. (His listing, like ours, included a few records supplied
by coopcrators.) Even with our better trans{)()rtation, more roads
providing access to colonics, and about 45 man-days a year specifi-
cally devoted to searches, in 4 years we found only 164 colonies.

2) We saw fewer non-breeding tricolors than Neff (1937). He
estimated that "unattaclied bands observed during tlie [6 years of]
field work totaled considerablv more tlian 50,000 birds." During 4
years, we observed fewer than 15,000.

3) We did not find any nesting areas approaching the size of some
Neff (1937) reported. For example, he described a large colony in
Glenn County where the birds were "active [in nest building] over
an area roughly 6.4 km (4 miles) east and west by 9.6 km (6 miles)
north and south." He estimated that another colony in Glenn
County contained at least 260.000 nests and covered virtually 24.3
ha (60 acres). Our most extensive colonies had continuous nesting
over only about 4 lia (10 acres). (Oiu^ large colony of about 25,000
birds was found in a 32.3-ha (80-acre) safflower field, but w^e do not
know if nesting was continuous throughout the field. The colony was
abandoned during egg-laying.)

4) Our largest colonies apparently contained far fewer birds than
Neff's (1937). He listed five colonies with at least 75,000 nests
(equivalent to about 112 500 birds). Our largest colony contained
only about 30,000 birds, and fewer than 20,000 of these actually
completed tlieir nesting eycle. In attempting to estimate the popula-
tion of his largest colony (in (Jlcnn County), Neff "gave up in
despair with the thought that an estimate of 250,000 adults was ri-
diculously low." This figure is considerably larger than the highest
vearlv total we recorded for all colonies (181,800 birds), in 1969.

5) We found fewer total tricolors than Neff (1937). During his 6
years of study, he found more than 1.5 million nests, equivalent to
more than 2.2 million breeding birds, or more than 375,000 a year.
During 1969-1972, we found about 532,000 breeding birds, or about
133.000 a year. The dilVcrcncc was esi)ecially obvious in the major
rice-growing counties (Butte, Colusa, Glenn, Sutter, Yolo and Yuba)
of the Sacramento Valley where Neff (1937) found all of his very
large colonies, and an aviM-ago of about 1()1,000 nests, or more than
241,000 breeding birds a year. In comi)arison, our 4-year total for the
major rice-growing counties was about 244,000 birds (Table 5).

Tricolors have apparently not benefited from increasing rice culture
in the Central Valley as suggested by Neff (1937) and Orians (1961a,
1961&). Rice acreages have increased nearly fourfold during the last
30 years, from about 50,625 ha (125,000 acres) during the 1940 's to
nearly 202,500 ha (500,000 acres) in 1954, then down to 91,530 ha

TRICOLORED BLACKBIRD BREEDING STATUS 179

(226,000 acres) in 1957, and finally to 174,960 ha (432,000) acres in
1968 (Johnston and Dean 1969). Thus, if rice culture is beneficial to
the tricolor, then this benefit must have been offset by one or more
detrimental factors. Perhaps the increase in land use and intensified
pesticide use in recent years have limited the food supplies essential for
tricolor breeding.

There is no question that suitable nestino; habitat for tricolors has
been lost in some local areas. For example, Neff (1937) and later Lack
and Emlen (1939) studied colonies near Davis (Yolo County), but
little or no nesting habitat exists there now and we found no breeding.
There is now no nesting habitat near Kiego Road in Sacramento
County where Orians (1961a) found several colonies. South of the
Central Valley, Collier (1963) studied colonies at Cache Creek (Kern
County), which has since been covered by a freeway, and at San Fer-
nando Reservoir (Los Angeles County), which has been drained for
housing development. Nevertheless, we doubt that local losses of habitat
have contributed significantly to any overall population decline. In
fact, like Neff (1937), we found that tricolors in most areas, including
the Sacramento Valley, leave many marshes and other apparently suit-
able nesting sites unused each year. Clearly, further research on the
requirements for tricolor breeding is needed to help isolate a possible
cause for the species' apparent decline.

Also important are the questions of when the decline began and
Avhether it is continuing. Unfortunately, none of the studies conducted
between Neff's (1937) and ours are complete enough to draw conclu-
sions about total population size in even a portion of the tricolors'
range. However, if significant observer differences can be ruled out, the
fact that Orians (1961a) found three colonies with 50,000 to 100,000
nests in the Central Valley as recently as the early 1960 's could indi-
cate that the decline is relatively recent. Further research is needed to
determine whether this downward trend, which may have reduced the
Central Valley population by more than 50%, is continuing, and
whether it has yet reached the point of concern.

ACKNOWLEDGEMENTS

For advice during the study and during preparation of the manu-
script, we thank Joseph L. Guarino, Willis C. Royall, Jr., Jerome F.
Besser and Ann H. Jones of the Denver "Wildlife Research Center. For
data on one or more tricolor breeding colonies we thank Lee R. Baker,
Dell 0. Clark, Alice E. Fries, Gary Nielsen, Bruce R. Norwitt, Randy
Parsons, Edward J. O'Neill, Donald S. Pine, Gene A. Sipe, Otis
Swisher, Robert C. Watsin, Robert L. Van Wormer, Joseph M. Welch,
Shirley Wells, Jack Wilburn, Vernal L. Yadon, and Jack M. Yardley.

LITERATURE CITED

Bent, A. C. 1965. Life histories of North American blackbirds, orioles, tanagers,
and allies. Dover Publications, Inc., New York. 549 p. (First published as U.S.
Nat. Museum Bull. 211, 1958.)

Collier, G. 1968. Annual cj'cle and behavioral relationships in the red-winged and
tricolorcd blackbirds of southern California. Ph.D. Thesis. Univ. Calif., Los Ange-
les. 374 p.

Emlen, J. T. 1941. An experimental analysis of the breeding cycle of the tricolored
red-wing. Condor 43(5) : 209-219.

180 CALIFORNIA FISH AND GAME

Johnston, W. E., and G. W. Dean. 1909. California crop trends: yields, acreages,

and production areas. Univ. Calif. Agr. E.\p. Sta. E.\t. Serv. Circ. 551. 12G p.
Lack, 1). 1954. The natural regulation of animal numbers. Oxford Univ. Press,

Ely House, London. 343 p.
. 19C8. Ecological adaptations for breeding in birds. Methuen and Co. Ltd.,

London. 409 p.
Lack, I)., and J. T. Emlen Jr. 1939. Observations on breeding behavior in tri-

colored red-wings. Condor 41(0) : 225-230.
Ncff, J. A. 1933. The tri-colored red-wing in Oregon. Condor 35(0): 234-235.
. 1937. Nesting distribution of the tri-colored rod-wing. Condor 39(1) : 01-

81.
. 1942. Migration of the tricolored red-wing in central California. Condor

44(2) : 45-53.
Orians, G. H. 1900. Autumnal breeding in the tricolored blackbird. Auk 77(4) :

379-398.
. 19Gla. The ecology of blackbird (Agelaius) social systems. Ecol. Monogr.

31(3): 285-312.

19Gl?j. Social stimulation within blackbird colonies. Condor 03(4) :

330-337.

Orians, G. H., and G. Collier. 1903. Competition and blackbird social systems.
Evolution 17(4) : 449-459.

Payne, R. B. 1905. The breeding seasons and reproductive physiology of tri-
colored blackbirds and redwinged blackbirds. Ph.D. Thesis. Univ. Calif., Berkeley.
279 p.

Richardson, C. 1901. Tricolored blackbirds nesting in Jackson County, Oregon.
Condor 03(0) : 507-508.

Calif. Fish and Game 61(4) : 181-200. 1975.

THE AGE AND GROWTH OF THE PACIFIC BONITO,

SARDA CHILIENSIS, IN THE EASTERN

NORTH PACIFIC^

GAIL CAMPBELL ' and ROBSON A. COLLINS

Operations Research Branch Department of Fish and Gome

An age and growth stud/ of the Pacific bonito, Sarda chiliensis, was
conducted between 1968 and 1973. Otoliths were used to establish the
ages of over 3,000 bonito, and the results verified by length frequency
samples, a tag and recapture experiment, and back-calculation of mean
length at each age. The results show that bonito grow rapidly during
their first 3 years of life, with much slower growth from 3 to 6 years
old. The mean length of each age group in the fishery is: age I — 51.5
cm (20.3 inches), age 11 — 63.3 cm (24.9 inches), age III — 69.5 cm (27.4
inches), age IV — 72.9 cm (28.7 inches), age V — 74.8 cm (29.4 inches),
and age Vi — 75.7 cm (29.8 inches).

INTRODUCTION

The Pacific bonito is an epipelagic schooling fish found along the
Pacific coast of both North and South America. This tuna-like species
is discontinuously distributed from Chile to the Gulf of Alaska, being
absent from the central coast of Mexico south into Panama. In the
North Pacific the species is most economically productive from Magda-
lena Bay in southern Baja California to Point Conception, California.
The growing importance of this species after 1957 in the California
sport and commercial catch has emphasized the need for information
on which to base management decisions.

During the early years, commercial fishermen using purse seines and
trolling gear averaged about 2,000 metric tons per year (Heimann and
Carlisle 1970). Commercial landings increased dramatically after 1966,
reaching 13,900 metric tons (MT) (15,400 short tons) in 1973 (Oli-
phant 1974), and averaging about 8,800 MT per year (9,700 short
tons), primarily because of increased demand for the canned product.

During the decade between 1947 and 1956 sport anglers using rod
and reel caught an average of 46,000 bonito per year. The bonito
sportcatch started on the upswing with the onset of anomalous warm
w^ater years in the California Current system in 1957 (Radovich 1961).
For unknown reasons, when the ocean waters off California returned
to cooler temperatures after 1960, the catch of bonito remained high.
In the years between 1960 and 1972 the sport catch averaged about 1
million fish per year and reached a record of about 2.5 million fish in
1964 (Thayer 1973). By 1968 bonito were ranked as the fourth most
important species to the partyboat industry (Young 1969). The peak
sportcatch of bonito occurs during August and September, however, it
gains exceptional recognition during the winter months when the young

' Accepted for publication April 1975.

^ Now with Anadromous Fisheries Branch, Tiburon, California.

(181)

182 CAI.IFORXIA FIRIl AXD OAME

bonito abound in the Avarm water discharges of coastal power plants.
The peak eomniereial catch occurs during September through Novem-
ber Avlien the larger fish are quite abundant near the nortliern C'lianncl
Islands off southern California and are readily available to trolling and
purse seine gear.

A research program to ascertain the age, growth and migration of
Pacific bonito in the eastern North Pacific was begun by the Depart-
ment in 19G8. The ])rogram consisted of two parts, a tag and recapture
experiment and an age and growth study. This paper covers the results
of the age and growth studies. The migration of bonito as determined
by the tag and recapture ex]icriin(Mit will be reported in another paper.

METHODS

Most fish age determination methods rely on the interpretation of
rings on scales, otoliths, or other bony structures of the fish. In the
course of this study, otoliths, scales and vertebrae were examined to
determine if they were suitable for age determination. Bonito scales
proved to be unreliable due to the high percentage of regeneration and
irregularity of the circuli. Vertebrae were potentially useful but were
more difficult to process and less legible than otoliths. Otoliths ap-
peared to be the most promising material and we decided to use them
as our principal age determination material. Otoliths have also been
successfully used by Department of Fish and Game management pro-
grams on Pacific mackerel, Scomber japonicus, a closely related species
(Fitch 1951), as well as northern anchovy, Encjraulis mordax (Collins
and Spratt 1969), and jack mackerel, Trachurus syDinictricus (Knaggs
and Sunada 1974).

SAMPLING

Material for this study was obtained through routine sampling of
the Pacific bonito landings at the canneries in San Pedro, California.
Commercial catclies landed here originate between central Baja Cali-
fornia and Point Conception, ('alifornia.

The details of the plan under which the samples were collected were
modified several times during the period of the age and growth study,
but basically involved the random selection of a boat load to be sampled
and the selection of a random subsample of either a fixed weight of
fish (1970-72), or a fixed number of fish (1968-69 and 1973-74), from
each load.

Samplers recorded the fork length (fl) in millimeters, the weight
to the nearest ounce, determined the sex and collected the head from
each fish sampled. The head was brought back to the laboratory for
removal of the otoliths.

Extraction of Otoliths

The otoliths are located in cavities in the posterior portion of the
skull. They were exposed by making a diagonal slice through the skull
anterodorsal to the eye on a plane which cuts midway through the
operculum. The largest pair of otoliths, the sagittae, Avere carefully
extracted with a pair of fine pointed forceps. After removal of the
enveloping tissue sac, tlie sacculus, the pair was placed in labeled gelatin
capsules which were stored in numbered coin envelopes.

PACIFIC BONITO AGE AND GROWTH

183

Age Determination

Otoliths were submerged in about 6 mm (^ incli) of water in a small
glass dish with a black plexighass bottom. They were examined under
a binocular microscope witli the aid of a narrow beam of light directed
toward the otolith at a low angle. With a magnification of 10 >< and
the proper reflected light, tlie alternating white (opaque) and dark
appearing (hyaline) zones could be counted (Figure 1). The number
of annuli, the legibility of each pair of otoliths, and condition (opaque
or hyaline) of the margin of each otolith were noted using the standard
terminology of Jensen (1965).

FIGURE 1. Pacific bonito otolith pair. Note alternating opaque and translucent (hyaline)
zones. The locations of annuli are marked on the lower left corner of the top
otolith. Photograph by Jack W. Schoit.

The difference in transparency between the opaque and hyaline zones
is apparently due to their content of organic matter (Fitch 1951).
Calcium carbonate and organic matter are added to the otolith during
the bonito 's period of rapid growth each summer. During tlie winter
however, the growth is slow and the zone contains much less organic
matter. The summer zone appears white and opaque in reflected light
because of the scattering of light by the organic matter while the winter
zone appears dark and translucent.

184: CALIFORNIA FISH AND GAME

Our criteria for interpreting otolith rings were based on Depart-
ment of Fisli and Game studies of Pacific mackerel (Fitcli 1951) and
northern anchovy (Collins and Spratt 19G9). For the purpose of this
study, we defined one year of growth as consisting of an inner opaque
zone (summer growth) and an outer hyaline zone (winter growth).
Since many otolith margins were difficult to interpret until a significant
portion of a zone had been formed, we established the criterion that a
year of growth was not complete until an opaque margin was evident
on at least 50% of the outer rim of the otolith. This convention helped
to establish consistency among the otolith readers. Some degree of un-
measureable error existed in the reading procedure, particularly in
dealing with the older age groups. The otoliths from animals up to 4
years old are highly legible (Figures 2, 3), but those from fish 4 years
and older tend to be heavil}^ calcified and thickened and to produce
two or more narrow opaque bands during summer growth. These bands
are quite narrow relative to the others and often are not complete
around the otolith; we termed them "fractured annuli". In our at-
tempts to interpret these fractured annuli we eliminated some and
consolidated others. An age was assigned to the fish by counting the
correct bands and noting the condition of the margin. No reference
was made to fish lengths when readers were establishing ages. The
distance between the focus of the otolith and the midpoint of each
opaque zone was measured using a micrometer eyepiece and a back-
calculation of the fish's length at each year in its life was made.
Although both otoliths were examined, only the best of the pair was
measured. A few of the otoliths were either deformed or too thickly
calcified and opaque to be read. "Whenever this occurred, one of the
pair of otoliths was legible and an age was assigned.

PACIFIC BONITO AGE AND GROWTH

185

FIGURE 2. Examples of otoliths from: A — 37.3 cm female, age O; B — 57.9 cm male, age
I; C — 64.2 cm male, age II; and D — 67.1 cm male, age III. Pbofographs by
Jack W. Schoff.

186

CALIFORNIA PMSH AND GAME

FIGURE 3. Otoliths from: A— 71.5 cm female, age IV; B— 72.4 cm female, age V; C— 72.2
cm male, age V; and D — 73.6 cm female, age VI. Photographs by Jack W.
SchoH.

PACIFIC BONITO AGE AND GROWTH

187

RESULTS
Otolith Readings

Ages were assigned to all 3,139 bonito examined. These fish ranged
from less than 1 to over 6 years, and in size from 23 to 79 em (9 to 31
inches) fl.

The lengths and ages from these fish were used to generate the con-
stants for a von Bertalanffy growth equation (Beverton and Holt,

1967).

Z,r=: 76.87 [l — e-o-62i5(«-o.4io)]

The curve was fitted to the data using a least squares computer program
(Abramson 1971, Tomlinson and Abramson 1961). The equation gives
the length (FL) at each age as; age I — 44.9 cm, II — 67.6 cm, III —
67.6 cm, IV — 71.9 cm, V— 74.2 cm, and V— 75.4 cm. Growth is rapid
during the first 3 years, tapering off to a relatively low rate during
the last 3 years.

To compare the growth predicted by this equation with the mean
length and range of the fish sampled from the fishery we calculated
the length of each age group at the mid-point of the fishing season by
adding 3 month's growth to the length at the time of annulus forma-
tion (^ -1-0.375). The mean length (FL) of each age group in the
fishery then is; age group I — 51.5 cm, II- — 63.3 cm, III — 69.5 cm,
IV— 72.9 cm, V— 74.8 cm, and VI— 75.7 cm.

90 r

I-

Lj» 76.87 [l-e

-0.6215 (t-0.4IO)

L«=768.7

N- 3^139

SAMPLE RANGE

A6E CLASS

FIGURE 4. Von Bertalanffy growth curve for Pacific bonito. For comparison the range and
mean lengths of each age group in the sample are plotted on the curve.

The Lm predicted by this equation is less than has been observed
by us in the catch, and is much less than the 102 cm (40-inch) fish
recorded by Roedel (1948). This may be due in part to the lack of fish
larger than 79 cm (31 inches) in the sample which was used to calculate
the growth curve. The 40-inch fish reported by Roedel (1948) is so far

188 CALIFORNIA FISH AND GAME

from our fjrowth curve that Fitch (Pers. Comm.) speculates that it may
have been an abnormally large nnreprodnetive "giant" such as
reported by Fitch and Lavenberg (1971) for Pacific mackerel {Scom-
ber japonicus) . Fish up to 82 em (32 inches) fl were observed in the
catch, but unfortunately no otoliths could be obtained from them.

Consistency of Otolith Readings
In order to test the consistency and reliability of the otolith reading
technique, a total of 2,076 otoliths was read independently by the two
readers. The frequency of agreement on the first reading varied between
61 and 87%. The two readers agreed on the age of better than 80%
of the otoliths in 3 out of the 4 years of samples. Where differences in
ring count occurred, a second examination was made by both readers
simultaneously. The frequency of agreement during the second reading
varied between 96 and 99.66%. The major discrepancy was due to
differences in interpretation of the condition of the margin on otoliths
from older fish. The relatively high degree of agreement indicates that
age determination of bonito from otoliths is consistent and reliable.

Validation of Age Determination from Otoliths
"We chose to validate the otolith method of age determination in four
ways: i) Observation of the change in the character of the otolith
margin over a year's time; ii) Back-calculation of length at each age
by proportion to otolith length; iii) Observation of the progression of
monthly length-frequency modes and; iv) Direct observation of the
growth of tagged fish.

Changes in the Ofolith Margin

The first hurdle in any age and growth study is to prove that the
zones which are being counted on the scales, otoliths, vertebrae, etc.
are formed annually. We noted the condition, opaque or translucent,
of the margin of every otolith examined and used the otoliths with less
than three annuli to graph the percent with either opaque or translu-
cent margins each month, for one year (Figure 5).

In July, 100 %o of the fish sampled had otoliths with opaque margins,
while between July and March this percentage decreased steadily to a
low of 19% in March. Between March and July there was a steady
increase in the percent of otoliths having opaque margins. This cyclic
change indicates that a new opaque zone is begun each year between
March and July and that a single opaque-hyaline zone pair is formed
each year.

These data along with what spawning information is available
(Pinkas 1961, Klawe 1961) indicate that a birthdate of July 1 would
be appropriate for establishing year-class memberships.

Back-Calculation of Length at Age

To further validate the annual nature of the zones, we back-
calculated the theoretical length of the fish at each age before it was
caught and compared these to lengths from the Von Bertalanffy
equation and to the age-length frequency obtained from sampled fish.
This method is based on the direct proportion between otolith size and
fish length and uses the formula L = LcOr/Om where L = length at
time of annulus formation, Lc = length at time of capture, Or = dis-

PACIFIC BONITO AGE AND GROWTH

189

o
a:

TRANSLUCENT

* ^* • • • • • • • • •• • • • .• •••••••>•

V • • 1' • • 1

■»

-^^

a.
<

FIGURE 5. Percent of bonito otoliths showing opaque and hyaline margins for each month
of the year.

tance from the otolith focus to the midpoint of the opaque zone in
question, and Om = the distance from the focus to the posterior margin.
In order to use this method there must be a direct relationship between
otolith size and the length of the fish. Otolith length Oi (cm) was
plotted against the fork length of the fish (cm) for 516 fish, and the
relationship appeared linear. A regression analysis yielded the equation :
Oi = 10-3(69.69 + 3.22 fl), with a standard error of 23.97 and a cor-
relation coefficient of 0.85.

The otoliths from 918 bonito were used to back-calculate lengths and
their means for each age group. These calculated mean lengths (fl)
were 47.9 cm for formation of the first annulus, 58.0 cm for the second
annulus, 64.3 cm for the third, 68.4 cm for the fourth, and 70.7 cm for
the fifth (Table 1). When these lengths were compared to the length-
frequency data, they matched the modes quite well (Figure 6). The
relationship of the calculated lengths to the observed lengths exhibited
a good correspondence and further validated the annual nature of the
zones.

190

CALIFORNIA FISH AND GAME

AUGUST

SEPTEMBER

OCTOBER

NOVEMBER

DECEMBER

JANUARY

^ .J-'^

FEBURARY

^ -

MARCH

APRIL

T 1 1 r

25 30 35 40

FORK LENGTH (CM)

FIGURE 6. Monthly length frequencies of bonito caught off southern California 1972-73.
The modes are marked.

PACIFIC BONITO AGE AND GROWTH

191

TABLE 1.

Back-Calculated len

gths at each age for Pacific Bonifo

Age group

Back-calculated lengths (cm fl)*

Number of
samples

4G.0
49.5
48.4
48.4
47.1

59.0
57.5
57.5
58.1

66.6
64.1
62.1

70.1
66.7

70.7

422

II . ...

102

III

248

IV ..........

124

47.9

58.0

64.3

68.4

70.7

Total 918

* Lengths correspond to length of fish in early to mid summer.

Modal Progression

In order to compare growth estimates from the growth equation to
field observations of growth, monthly length-frequency polygons were
constructed from data collected from all segments of the fishery dur-
ing 1972 and 1973 (Figure 6). The first mode, which we designated
the 1972 year-class, was followed for more than a year, during which
the change in the modal length matched the growth rate obtained from
the otoliths of 0 and I age group fish. The modal progression indicated
very rapid growth from about May or June until October, and almost
no growth from January through April. During periods of rapid growth,
fish in the first modal group gained about 2 em per month, while the
second mode fish grew 1 cm per month or less. Fish three years and
older (third mode) could not be separated into distinct age groups, but
it was evident that they grew very slowly. The modal lengths were
plotted on the von Bertalanify growth curve graph (Figure 7) in order
to compare observed growth to estimates obtained from otoliths. The
two curves fit quite well, lending further support to the otolith method.

Growth of Tagged Fish

Direct observations of growth can be obtained from a tag and recap-
ture experiment when lengtli measurements are taken from fish at both
release and recapture. These measurements can then be compared to the
calculated growth estimates derived from other methods. A tagging proj-
ect was launched in 1968, in conjunction with the start of the age and
growth study on bonito. To date, over 13,000 tagged fish have been re-
leased from research vessels, partyboats and bait receivers, and over
1,000 have been returned by sport and commercial fishermen. About
13% of the tag returns, or 140 fish, provided good, reliable (verified
length at time of capture) growth data (Table 2). This growth matched
that predicited by the von Bertalanify growth curve quite well (Figure
8). The most interesting recovery was of a fish at liberty 848 days (over
2 years) which grew from 40 cm (15.7 inches) at the time of release to
almost 68 cm (26.8 inches) when recaptured. This growth matched that
predicted by the growtli equation almost exactly. The growth of the 0
age group fish at liberty for short periods also agreed well with our pre-
dictions from growth curve data.

192

CALIFORNIA FISH AND GAME

>
u>

FORK LENGTH

(CM)

JUN-

SEP-

DEC-

MAR-

JUN-

SEP-

OEC-

MAR-

JUN-

SEP-

DEC-

MAR-

JUN-

8EP-

DEC-

MAR-

JUN-

SEP-

OEC-

MAR-

JUN-

SEP-

DEC-

MAR-

JUN-

SEP-

DEC-

_1_

ra
o

_1_

o
_1_

-4

at
o

FIGURE 7. Monthly modal lengths from figure 6 plotted against the von BertalanfFy growth
curve. • = mode 1, * = mode 2, * = mode 3.

PACiriC BONITO AGE AND GROWTH

193

(0
(A

FORK LENGTH (CM)

JUN
SEPH
DEC
MAR-
JUN-
SEP-
OEC-
MAR-
JUN-
SEP-
OEC-
MAR-
JUN-
SEP-
OEC-
MAR>
JUN-
8EP-
OEC-
MAR-
JUN-
3EP-
OEC
MAR-
JUN-
SEP

]

-L.

to
o

at
o

0»

FIGURE 8. The growth of selected tagged fish against the von Bertalanffy growth curve.
Fish at liberty less than 2 months have been omitted.

194

CALIFORNIA FISTI AXD GAME

TABLE 2. Growth Data from Recovered Tagged Bonito

Date of
release*

115/09.
122/C9.
122/09.
133/09.
133/09.
133/09.
130/09.
157/09.
104/09.
104/09.
189/09.
233/70.
237/70.
247/70.
247/70.
248/70.
248/70.
248/70.
252/70.

70/71.

25/72.
154/72.
102/72.
248/72.
249/72.
249/72.
249/72.
250/72.
250/72.
250/72.
250/72.
250/72.
348/72.
251/72.
271/72.
279/72.
282/72.
300/72.
209/72.
209/72.
300/72.
110/73.

70/73.
312/72.
271/72.
279/72.
289/73.
280/72.
270/72.
270/72.
281/72.
282/72.
283/72.
289/72.
292/72,
300/72.
303/72.
300/72.
307/72.

70/73.
279/72.
130/73
209/72

94/08

Length at

release

(mm fl)

455
430
450
430
400
405
395
425
420
440
440
570
570
320
310
580
330
330
520
430
570
505
745
570
303
575
541
504
598
500
544
351
401
545
380
585
700
380
382
300
395
380
415
390
380
390
425
385
350
370
395
595
720
390
380
380
435
370
380
430
405
394
307
440

Date of
recovery*

185/09
127/09
140/09
144/09
144/09
190/09
149/09
182/09
191/09
209/09

99/70
234/70
250/70
279/70

55/71
205/70
272/70
205/70
271/70
114/71

04/72
177/72
277/72
287/72
250/72
257/72
287/72
272/72
207/72
265/72
204/72
203/72
208/73
201/73
104/73
353/72
332/72

29/73

34/73
118/73

15/73
119/73
104/73
108/73
104/73
105/73
201/73
198/73
288/72
294/72

21/73
300/72
302/72
304/72
302/72
309/72
316/72
320/72
325/72
131/73
157/73
104/73
330/72
143/08

Length at
recovery
(mm iL)

492
432
438
430
400
410
395
420
428
444
483
553
574
338
302
507
347
325
516
419
507
495
752
551
355
560
545
559
599
559
535
355
457
018
457
005
092
391
432
400
400
380
419
402
405
432
445
438
349
303
443
584
720
390
308
378
414
303
307
427
440
395
387
440

Days at
liberty

270

174

116

225

315

198

132

210

103

200

253

113

285

107

243

Growth

(mm)

-12

-17

-13

-5

-4

-11

-3

-10

-19

-8

-15

-5

-1

-9

-8

-7

-11

-12

-2

-21

-7

-13

-9

Calculated

length one

year after

release (mm)

645
552

474

439
524
472

497

074
519
419

578

707

578
018

455
489
033
427
082

425
520
438
448

405
417
420
451
490
453
553

500

465
435
485

PACIFIC BONITO AGE AND GROWTH 195

TABLE 2. Growth Data from Recovered Tagged Bonito — Continued

Date of
release*

131/68..
131/08..
145/08..
145/68..
145/08-
145/68..
145/08..
263/08..
263/68..
271/68..
296/68..
108/69.-
184/73.-
129/69..
201/73..
271/72-.
187/73-
278/72-
282/72-
173/73-
213/73-.
228/73-
258/72-
230/73-

89/73--
280/72-

76/73-

89/73-

261/72-

271/72-

187/73-

170/73..

250/72..

251/72-.

251/72-

256/72..

258/72..

261/72..

264/72..

269/72..

269/72-.

271/72-.

276/72-,

276/72.,

276/72.

258/72.

306/72.

247/70.

273/70.
08/71.
68/71.
70/71-

152/72.

258/72.

145/68.

Length at

release

(mm fl)

438

476

420

455

405

440

450

490

510

410

560

440

455

400

485

390

445

395

410

405

472

408

365

515

405

370

415

460

380

370

420

418

534

545

560

367

352

355

350

360

370

560

331

370

348

377

380

370

375

303

377

383

407

356

365

370

320

360

415

395

370

450

336

430

Date of
recovery*

140/08
142/08
145/08
147/68
147/68
158/68
201/08
272/68
275/68
309/68
30/69
109/69
190/73
247/71
277/73
228/73
240/73
249/73
251/73
289/73
282/73
360/73
245/73
315/73
96/73
91/73
104/73
108/73
99/73
100/73
194/73
216/73
291/72
287/72
266/72
280/72
327/72
279/72
309/72
288/72
305/72
285/72
285/72
292/72
283/72
313/72
283/72
289/72
311/72
283/72
291/72
288/72
301/72
306/72
329/72
334/72
298/70
26/71
87/71
78/71
80/71
183/73
201/73
291/68

Length at
recovery
(mm fl)

430

470

410

455

405

442

455

480

510

407

565

425

457

086

520

413

460

457

432

442

520

507

481

557

406

395

419

470

415

394

422

420

559

547

552

370

364

370

363

378

572

338

389

351

377

380

370

380

366

381

399

362

373

360

343

381

413

400

368

552

457

448

Days at
liberty

12
1
3
3

101

848

77
322

53
336
334
117

70
133
353

86
8

177

203

195
8
47
42
37
16
25
72
22
52
28
45
22
17
24
15
45
13
19
41
8
16
13
26
31
72
29
52

119
20
11
11

390

311

147

Growth
(mm)

-8

-0

-10

-3

-15

280

lie

-8

-2

-8

-10

-2

102

121

Calculated

length one

year after

release (mm)

492

482

578

003
523
651
416
548
462
434
520
722
575
485
094
451
422
465
643
443
415
511
589
751
565

455
413
604
490
399
435
759
481
598
421

548

420
500
468

427
406

481
424

561

544
478
475

196 CALIFORNIA FISH AND GAME

TABLE 2. Growth Data from Recovered Tagged Bonito — Continued

Date of
release*

Length at

release

(mm fl)

Date of
recovery*

Length at
recovery

(mm fl)

Days at
liberty

Growth

(mm)

Calculated

length one

year after

release (mm)

115/09..-

420
435
390
380
40".
400
345
500
540
360
405
330

228/69
229/69
192/09
247/09
245/09
257/09
329/72
300/72
336/72
0/73
48/73
301/72

445
480
410
414
430
438
309
597
559
404
432
308

114

101

115

101

122

134

25
45
20
34
25
38
24
31
19
44
27
38

500

129/09

598

133/09

512

133/09

488

157/09

508

157/09 ---

537

248/72

452

250/72 .-.

765

251/72...

621

251/72

492

281/72

479

292/72

528

* Julian Date i.e. 361/72 is the 361st day of 1972 or December 26th, 1972.

In addition, we plotted growth of the tagged fish (cm) against days
at liberty and compared the results with the predicted length changes
from the growth curve. The resulting scatter diagram from the tagging
data appeared linear, so a linear regression analysis was performed.
The equation of best fit was Y = —0.605 + 0.27X with a correlation
coefficient of 0.89 and a standard error of 1.553 (Figure 9). The dia-
gram indicated that the growth rate of the tagged fish was slightly less

I4jO-

I2D-

10.0-

4j0-

20-

>**

• ••

-za-

— r—

— I

120

— I —

ISO

leo

DAY3

1 1

210 24a

AT LIBERTY

— I

270

— I —
300

— I —
330

360

390

FIGURE 9.

Scatter diagram of length changes of tagged fish. Dot-dash line is straight line
of regression. Dashed line is straight line of regression forced through the origin.
Dotted line is expected length changes derived from von Bertalanffy grov»rth
equation.

PACIFIC BONITO AGE AND GROWTH

197

than the predicted values but still was in good agreement. A fish with
a tag may not grow at a normal rate (Jensen 1967). Subnormal growth
rates are commonly observed in tagging studies. The high degree of
variation about the line was most likely due to the lack of accuracy in
measuring a live, active fish.

Weight-Length Relationship

A weight-lengtli relationship was determined for bonito based on a
sample of 2,824 fish landed at the canneries at Terminal Island, Cali-
fornia during 1969 tlirough 1973. These fish ranged in weight from 200
to 7657 gms (0.4 to 16.9 lbs) and in length from 29 to 77 cm (11 to 30
inches). The least squares method was used to calculate the regression
of weight (grams) on length (millimeters) for each sex. The equation
of best fit for the males was W = 7.26083 X lO-cL^-^O'-'o and for the
females W = 7.93187 X lO-^L^os^ss tj^^ composite length-weight equa-
tion was W = 7.62728 X lO-^L^ o89G2 ^^jtli a standard error of 0.757 and
a correlation coefficient of 0.99. The 95% upper confidence limit of the
exponent was set at 3.10588 and lower limit set at 3.07335 (Figure 10).

14.0-
ISA-
IS.O-
II.O
10.0
ftO-
8.0

I-

2 6.0-

5.0-
4.0-
3.0-

W- 7.62728 X |0-*L^°896Z

-I — I — r-

10 20

— I—
30

— I — ' — r-

40 50

—I —

— 1—
70

— I—
80

90 100

FORK LENGTH (CM)

FIGURE 10. Length-weight relationship.

Length Conversions

Since project personnel use fork length in measuring bonito and fish-
ermen often use total lengths, a conversion factor was derived based on
273 fish sampled from sportboats and canneries. Mean fork length for
each 0.5 cm (0.2 inch) interval was plotted against its corresponding

198

CALIFORXIA FISH AND GAME

mean total lenj^tli. The resulting grapli indicated lliat the relationship
■\vas linear, so a linear regression equation was computed: Total lengtli
= 4.05 + 1.02 fork length -witli a standard error of 1.11.3 and a corre-
lation coefficient of O.DO (Figure 11).

7S.

69-

3 60-1

Z
111

-J- 55'

K
O
b.

I- 45H

40 ^

TL« 4.05*I.02FL
N»273

— I—
7S

— I—
4S

CENTIMETERS TOTAL LENGTH

— rr-
50

(TL)

FIGURE 11. Relationship between fork and total length.

SUMMARY AND CONCLUSIONS

All age and groAvth study of Pacific bonito Avas undertaken by the
California Department of Fisli and Game to provide information for
ultimate management of this rapidly expanding fishery.

Otolitlis obtained from fish lauded by the commercial fleet at San
Pedro, California, from lOfiS to 11178 Avere used to establish ages for
more than 3,000 bonito. These otoliths were read and used to construct
an age-length frequenc}- and to obtain the constants for a von Ber-
talanffy growth curve.

PACIFIC BONITO AGE AND GROWTH 199

The age determination method (otoliths) was validated by several
techniques. Tlie annual nature of the zones on the otoliths was demon-
strated by the cyclic character of the otolith margin throughout the year
and by the comparison of back-calculated fish lengths. Observed growth
rates from lengtli-frequency modes and tagging data correlated well
with the growth rates from otolith reading. Two readers examined the
otoliths independently and then simultaneously. The relatively high
degree of agreement attained both times indicated good consistency in
the method.

A weight-length equation was derived based on nearly 3,000 fish, and
an equation was computed for converting total length to fork length.

Otoliths are deemed reliable for determining the age of bonito, and
we recommend that they be used in any future management program.

ACKNOWLEDGEMENTS

Many Department personnel have contributed substantially to this
study since its inception in 1968. Foremost among those deserving spe-
cial mention is Kevin Farnum, who spent many hours learning the
otolith reading technique. John Geibel and Brian Thayer coordinated
the sampling and tagging projects until their transfers in 1969 and
1973, respectively. John Seapin carried out the waterfront sampling
from 1970 through 1973.

Seasonal employees Harvey Pearson, Kenneth Bolding, Robert Dan-
tas, Rodney Brashear, Donald Schultze, Darlene Osborne, and Dennis
Henley all were involved in measuring, taking otoliths, and tagging
fish. Other seasonal and permanent employees, too numerous to men-
tion, participated in our tag and release experiment.

The captains and crews of the N. B. SCOFIELD and KELF BASS
assisted immeasurably in the work at sea.

Harold B. Clemens and John E. Fitch gave valuable advice and
counsel during the study, and Eric Knaggs reviewed the manuscript.

We sincerely offer our thanks to all these persons whose contributions
were an integral part of the success of this study.

200 CALIFORNIA FISH AND GAME

REFERENCES

Abramson, Norman J. 1971. BGC-2 von Berfalanffy Rrowth nirvo fittinp:, 2.( — )1
1-1.3. In Computer programs for fi.sh stock a.ssessmont. F.A.O. Fish Tech. Paper,
(101) : V.P.

Beverton, R. J. H., and S. J. Holt. lOCT. On the dynamics of exph)ited fish popu-
lation. London. II. W. Stationary Off. 533 p.

Collins, Robson A., and J. D. Spratt. 1900. Age determination of northern an-
chovies, EngrauUs mordax, for otoliths, p. 39-54. In James D. Messersmith.
The northern anchovy (Engraulis Morthix) and its fishery. Calif. Dept. Fish and
Game, Fish Bull.. (147) : 1-102.

Fitch, John E. 1951. Age composition of the southern California catch of Pacific
mackerel 1939-1940 through 1950-51. Calif. Dept. Fish and Game, Fish Bull..
(83) : 1-73.

Fitch, John E.. and Robert J. Lavenberg. 1971. Marine Food and Game Fish of
California. Univ. of Calif. Press, Berkeley. 177 p.

Heimann, Richard F. G.. and John G. Carlisle. Jr. 1970. The California marine
fish catch for 1968 and historical review 191G-G8. Calif. Dept. Fi.sh and Game,
Fish Bull., (149) : 1-70.

Jensen. All)ert C. 19G5. A standard terminology and notation for otolith readers.
ICNAF Research Bull. (2) : 5-7.

. 1967. Effects of tagging on the growth of cod. Amer. Fisheries Soc,

Trans., 96(1) : 37-41.

Klawe, Witold L. 1961. Notes on larvae, juveniles, and spawning of l)onito
(Sarda) from the eastern Pacific Ocean. Pacific Science XV, (4) : 487—193.

Knaggs, Eric H., and John S. Sunada. 1974. Validity of otolith age determina-
tions for jack mackerel. Trachurus symmetriciis, from the southern Californi:i bight
area. Calif. Dept. Fish and Game, Mar. Resour. Tech. Rpt., (21) : 1-11.

Oliphant, Malcolm S. 1974. Statistical report of fresh, canned, cured, and manu-
factured fishery products for 1973. Calif. Dept. Fish and Game, Circular, (48) :
1-19.

Pinkas, Leo. 1961. Descriptions of postlarval and juvenile bonito from the east-
ern Pacific Ocean. Calif. Fi.sh Game, 47(2) : 175-18.^.

Radovich, John. 1961. Relationship of some marine organisms of the northeast
Pacific to water temperatures particularly during 1957 through 1959. Calif. Dept.
Fish and Game, Fish Bull.. (112) : 1-62.

Roedel, P. 1948. Common ocean fishes of the California coast. Calif. Dept. Fish
and Game, Fish Bull., (68) : 1-150.

Thayer, Brian D. 1973. The status of the Pacific bonito resource and its man-
agement. Calif. Dept. Fish and Game, Mar. Re.sour. Tech. Rpt., (7) : 1-16.

Tomlinson, Patrick K.. and N. Abramson. 11X51. Fitting a von BertalanfTy growth
curve by least .square including tables of polynomials. Calif. Dept. Fish and
Oame, Fish Bull.. (116) : 1-69.

Young, Parke H. 1969. The California partyboat fishery 1947-1967. Calif. Dept.
Fish and Game, Fish Bull., (145) : 1-9.

Calif. Fish and Game 61 (4) : 201-208. 1975.

PARASITES OF FISHES FROM THE SACRAMENTO-
SAN JOAQUIN DELTA, CALIFORNIA^

GARY H. HENSLEY^ and F. M. NAHHAS
Department of Biological Sciences, University of the Pacific, Stockton, California 95211

Between June of 1972 and June of 1973, 545 fishes representing 28
species were examined, revealing the presence of the following
parasites:

Protozoa: M/xobo/us koi Kudo, 1920 from Cyprinus carpio.

Trematoda: Oacfyfogyrus extensus Mueller and Van Cleave, 1932 from
Cyprinus carpio; C/eidodiscus price! Mueller, 1936 from Ictalurus catus,
I. melas, Morone saxatilis, and Chaenobryttus gulosus; Posthodiplostomum
minimum centrarchi (MacCallum, 1921; Dubois, 1936) Hoffman, 1958 from
Chaenobryffus gulosus and Lepomis macrochirus; Clinostomum mar-
ginatum (Rudolphi, 1819) from Chaenobryffus gulosus; and Alloglossidium
corti (Lamont, 1921) Mueller, 1930 from Ictalurus catus, I. nebulosus,
and f. punctafus.

Cestoda: Atraetolytocestus huronensis Anthony, 1958 from Cyprinus
carpio; Khawia iowensis Calentine and Ulmer, 1961 from Cyprinus
carpio; Corallobothrium giganteum Essex, 1927 from Ictalurus catus, I.
punctatus, and f. melas; Corallobothrium fimbriatum Essex, 1927 from
Ictalurus catus, I. punctatus, and I. melas; Bothriocephalus claviceps
(Goeze, 1782) Rudolphi, 1810 from Lepomis macrochirus; Pelichniboth-
rium speciosum Monticelli, 1889 from Alosa sapidissima; and Lacistor-
hynchus sp. from Alorone saxatilis.

Nematoda: Philometra carassii (Ishii, 1934) from Carassius auratus;
Capillaria catenata Mueller and Van Cleave, 1932 from Cyprinus carpio;
Contracaecum brachyurum (Ward and Magath, 1917) from Ictalurus
catus, Morone saxatilis, Pomoxis nigromaculatus, and Alosa sapidissima;
Contracaecum spiculigerum (Rudolphi, 1809) from Ictalurus nebulosus;
Raphidascaris sp. from Alosa sapidissima; Metabronema salvelini (Fujita,
1922) from Pogonichthys macrolepidotus; and Sp/roxys sp. from /Morone
saxatilis,

Hirudinea: lllinobdella moorei (Meyer, 1940) Meyer, 1946 from
Ictalurus catus.

Crustacea: Lernaea cyprinacaea Linnaeus, 1761 from Ictalurus catus,
Mylopharodon concocephalus, Orthodon microlepidotus, Pogonichthys
macrolepidotus, and Ptychocheilus grandis.

New geographic distributions include: Myxobofus koi Kudo, 1920
(Protozoa); Afracfo/ytocestus huronensis Anthony, 1958; Khawia iowensis
Calentine and Ulmer, 1961; and Bothr/ocepha/us claviceps (Goeze, 1782)
Rudolphi, 1810, (Cestoda); Philometra carassii (ishii, 1934); Capillaria
catenata Mueller and Van Cleave, 1932; and Contracaecum brachyurum
(Ward and Magath, 1917), (Nematoda); lllinobdella moorei {Meyer,
1940) Meyer, 1946 (Hirudinea).

A list of fishes negative for parasites is included.

1 Accepted for publication October 1974.

2 Biological Sciences, Los Medanos College, 2700 East Leland Rd., Pittsburg, Califor-

nia 94565

(201)

202 CALIFORNIA FISH AXD GAME

INTRODUCTION

There have been three major studies eoneenii'd whh j)arasites of
freshwater fishes of California. Haderlie (1953) summarized research
up to 1953 and conducted a jjfeneral survey of the parasites of fishes of
northern California. From 2.010 fishes represent in;u: 36 species exam-
ined from 1947 to 1930, he obtained a total of 59 species of helminth,
copepod, and hirudinian parasites. Alonp: with the taxonomic study,
Haderlie attempted to correlate relative occurrence of the parasites
with various ecolofrical habitats.

Haderlie examined a few fish from the San Pablo Keservoir, Lake
Temescal, Lake Hinman, and the Napa River, about 80 km (50 miles)
west of the Sacramento-Ran Joaquin Delta. There is no indication in
his paper as to the type of parasites encountered or the frequency of
parasitism in these rep:ions.

Edwards and Nahhas (1968) investif^ated the parasites of fishes of
the Sacramento-San Joaquin Delta and compared their findings with
those of Haderlie. During 1966 and 1967, 236 fishes representing 26
species were examined resulting in the recovery of 12 parasites of
which six were digenea, five cestodes, and one acanthocephalan.

Miller, Olson, and Miller (1973) reported the results of an investiga-
tion in which 480 fishes representing 13 species were collected from
13 reservoirs in southern California. P'our digeneans, seven monogeans,
five cestodes, one nematode, one acanthocephalan, and one hirudinean
are reported.

Less extensive work has been done bv Wagner (1953), Wales (1958),
Colley and Olsen (1963), Miller, L. W. (1967), Miller, R. L. (1967),
and Heckman (1974). The protozoan parasites of California fishes
have been studied bv several authors in separate articles: Jameson
(1931), Noble (1943," 1950), Davis (1947), Wales and Wolf (1955),
Leitritz (1960), Becker (1964), Becker and Katz (1965), ;ind Yasntake
(1970).

In the central region of the Sacramento-San Joaquin Valley, the
monogenetic fauna Avas investigated extensively by Mizelle and co-
workers: Mizelle and Arcadi (1945); Mizelle et al. (1956); Mizelle.
Toth, and Wolf (1961); Mizelle (1962); Mizelle and Crane (1964);
Mizelle and Price (1964) ; Price and Mizelle (1964) ; Mizelle and Krit-
sky (1967fl, 1967&) ; Crane and Mizelle (1968); Kritsky and Mizelle
(1968) ; and Mizelle and McDougal (1970).

A report from Van Cleave and Haderlie (1950) deals with acantho-
cephalans found in California.

Crustaceans and molluscans from California have been described by
Wilson (1908) and Murphy (1942).

The purpose of the present study, whicli was conducted between
June 1972 and June 1973, was to extend previous parasitological
investigations of the San Joaquin area fishes, with emphasis on their
helminthic fauna. One protozoan, found in large numbers, is however
included. A brief discussion is given for all parasites encountered for
the first time in California.

FISH PARASITES 203

SAMPLING AND EXAMINATION OF FISH

The major site of collection was the Fish Screen, Bureau of Keclam-
ation, Department of the Interior at Tracy, California. A small number
of fish were taken from various sloughs in the Stockton area. In all, 545
fishes were examined. Positive specimens resulted in the recovery of
one protozoan, two monogeneans, three digeneans, seven cestodes, seven
nematodes, one hirudinean, and one copepod. No parasites were found
in 46 fishes belonging to 9 genera.

Fish were obtained by hook and line, dip net, seine, and by hand.
After collection, the fish Avere brought alive to the laboratory, segre-
gated into groups, killed, and immediately examined to minimize
migration or loss of parasites.

Before removing the internal organs, each fish Avas examined for
external parasites. The internal organs were removed from the host,
separated, and placed in 0.7% saline solution. The heart, liver, gall
bladder, urinary bladder, caeca, and mesenteries were examined by
teasing the tissues apart with dissecting needles under a dissecting
microscope. The stomach and intestine were cut longitudinally to expose
the lumen and its contents.

After removal from the host, the parasites were processed according
to standard methods. Measurements are in millimeters unless otherwise
noted. New host records are indicated by an asterisk. The numbers in
parentheses following host name represent the number of individuals
that harbored that particular parasite (numerator) and total number
of fish examined (denominator). ,

PARASITES AND FISHES ENCOUNTERED

PROTOZOA

Myxobolus koi Kudo, 1920

Host: Cyprinus car pio hinnaeus (1/50)
Site : Encysted on gills

Description based on hundreds of spores, measurements on twenty:
Cyst white in color in live material 0.35-0.80 mm in diameter; spores
pyriform, 12-15 /x long by 7-10 fi wide ; posterior processes and shell
striations absent. Polar capsules two, pyriform Mith coiled filament,
equal or somewhat subequal in size, each 7-10 /x long by 2-3 /x wide.
Sporoplasm finely granular with an iodinophilous vacuole; sporoplasmic
nuclei indistinct.

At least 70 species have been described in the genus Myxololus
Biitschli 1881. Most of the species are histozoic parasites of freshwater
fish; few are marine; one is parasitic in an annelid, and one in an
amphibian. The chief criteria in classification include host and tissue
specificity in addition to size and shape of the spore, and number of
polar capsules. Infected tissues include brain, spinal cord, intestine,
liver, gall bladder, kidneys, spleen, connective tissues, body cavity,
cutaneous and subcutaneous tissues, muscle, eye, fins, and gills.

204 CALIFORNIA FISH AND GAME

Cyprimis carpio is known to liarbor 16 species of Myxoholus, four of
■which are from the frills: ,1/. cyprinicoJa Reuss, 1006 from various
localities in Europe, M. flUpsoidcs Tlu'lohan, 1892 from Russia, 3/. koi
Kudo, 1020 and .1/. ioyamai Kudo, lf)15 from Japan and Russia, respec-
tively. Although several species have been rei)orted from North Amer-
ican carp, none were recovered from the gills of Cyprimis carpio.

The present specimens agree Avith the description of 71/. koi Kudo,
1920 in size, shape of spores, and characteristics of the capsules. The
onl}^ difference noted is the size of the cyst given by Kudo (1920) as
230 jx in maximum diameter, whereas in the present study cysts were
larger, ranging in size from 350 to 800 /x. As far as can be determined,
this is the first record of this parasite outside Japan.

MONOGENEA

Dactylogyrus exfensus Mueller and Van Cleave, 1932

Host: Cyprinus carpio J Animeus (9/50)
Site: Gills

Cleidodiscus pricei Mueller, 1936
Hosts: Ictalurus catus (Linnaeus) (6/137)

^Ictalurus melas (Rafinesque) (7/33)
*Morone saxatilis (Walbaum) (1/81)
'■'Chacnohryttus gulosus (Cuvier) (1/7)
Site : Gills

DIGENEA

Posthodiplostomum minimum cenfrarchi (MacCallum, 1921;
Dubois, 1936) Hoffman, 1958
Hosts: Chaenohryttus gulosus Cuvier (3/7)

Lcpomis macrochirus Rafinesque (9/33)
Site: Encysted on the heart and liver

Clinostomum marginatum (Rudolphi, 1819)

Host: Chacnohryttus gulosus (Cuvier) (1/7)
Site : Encysted on heart

Alloglossidium cor// (Lamont, 1921) Mueller, 1930

Hosts: Ictalurus catus Linnaeus (7/137)

Ictalurus nchulosus (LeSueur) (4/9)

Ictaliirtis punctatns Hafiuefique (1/9)
Site : Intestine

CESTODA

Atracfolyfocesfus huronensis Anthony, 1958

Host: Cjiprinus carpio, '[j'mnaews (1/50)
Site : Intestine

This species, first described from the same host in IMichigan, was also
found in Oklahoma. Its recovery from Cyprimis carpio in California
confirms IMackiewicz's belief of its Avide geographic distribution (J. S.
Mackiewicz, State University of New York, pers. comm.).

Khawia iowensis Calentine and Ulmer, 1961
Host: Cyprimis carpio, Linnaeus (3/50)

FISH PARASITES 205

Site : Intestine

Khawia iowcnsis, a common parasite of Cyprinus carpio, is known
from Iowa, Wisconsin, and Oklahoma. It is here reported for the first
time from California. Its identification, and that of Atractolytocestns
hiironensis, was confirmed by Dr. Mackiewicz.

Corallobothrium giganteum Essex, 1927

Hosts: Ictalurus catus (Linnaeus) (13/137)

Ictalurus punctatus Eafinesque (1/9)

*Ictalurus mclas (Rafinesque) (1/33)
Site : Intestine

Corallobothrium fimbriafum Essex, 1 927

Hosts: Ictalurus catus (hmnaeua) (55/137)

Ictalurus punctatus Rafinesque (5/9)

Ictalurus melas (Rafinesque) (1/33)
Site : Intestine and stomach

Bothriocephalus clav'iceps (Goeze, 1782) Rudolphi, 1810

Host: Lepomis fnacrochirvsHahnesqne (2/33)
Site : Intestine

Haderlie (1953) found larval forms of this genus in Lepomis macro-
chirus and L. cyancllus. The present material, represented by 2 mature
specimens, is the first record of the adult form in California.

Pelichnibothrium speciosum Monticelli, 1889

Host: * Alosa saindissima (,^Yl\son) (1/17)
Site : Intestine

Lacistorhynchus sp.

Host: Morone saxatilis (Walbaum) (1/81)
Site : Encysted in muscle

NEMATODA
Pbilometra carassi'i (Ishii, 1934)

Host: Carassius auratus (JAnnixeus) (10/20)
Site : Between caudal fin rays

At least forty-nine species have been described in the genus Philo-
mctra Costa, 1845, five of which are known from the United States.
The unique site of infection and the host suggest P. carassii from
Japan, P. sanguinca from Europe, or P. trilahiata from Russia. The
Russian species was not available for study, and a comparison of the
present material with the other two species suggests P. carassii. This
species was originally reported from Japan by Ishii (1934), being
found between the caudal fin rays of Carassius auratus. The only other
report of this species is from Ohio. The present report establishes a
new geographic distribution.

Capillaria cafenata Van Cleave and Mueller, 1932

Host: '^Cyprinus carpio (Linnaeus) (3/50)
Site : Intestine

This species, originally described from Oneida Lake fishes, is also
known from Idaho and AVyoming. The present report establishes a new
geographic distribution and host record.

206 CALIFORNIA FISH AND GAME

Contracaecum brachyurum (Ward and Magath, 1917)
Hosts: *Ictalun(s catits (JAuuixonH) ((),i;57;
'^Moronc saxatilis (Walbauni) (2/81)
*Pomoxis nifjromaculatus (LeSueur) (1/44)
*Alosa sapidissima (Wilson) (1/17)
Sites : Intestine and caeca

Twenty-two specimens in various dejrrees of maturity were collected
from the above four hosts. This report establishes a new geographic
distribution record.

Contracaecum spiculigerum (Rudolph!, 1809)

Host: let alunis 7ichuIosus {Le^ueur) (1/9)
Site : Encysted in mesentery

Raphidascaris sp.

Host: Alosa sapidissima {'Wilson) (7/17)
Site : Coelom and mesentery

Mefabronema salvelini (Fujito, 1922)

Host: '^Fogoniclithys macrolepidotus (Ayres) (3/21)
Site : Intestine

Spiroxys sp.

Host: Morone saxatilis (AValbaum) (13/81)
Sites : Intestine, stomach, caeca, and mesentery

HIRUDINEA
lllinobdella moorei (Meyer, 1940) Meyer, 1946

Host: Ictalurus catus (hinnaeus) (24/137)
Site : Skin, gills, and fins

Four of the five known species in the genus lUinohdcIIa are Ameri-
can: I. alha Mever, 1940; /. rlongata Mever, 1940; 7. vworci (Mever,
1940) Meyer, 194G; and I. richardsoni (Meyer, 1940) Meyer, 1946. Had-
crlie (1953) has recorded lUinohdcUa sp. from Ictalurus catus and I.
nchulosiis in California.

CRUSTACEA
Lernaea cyprinacaea Linnaeus, 1761

Hosts: Ictalurus caius (Jjinnaeus) (21/137)

Mylopharodon concoccphalus (Baird and Girard) (4/12)

Orthodon 7nicroIcpidotus (Ayres) (1/9)
*Po(jomchtliys macrolcpidotus (Ayres) (1/21)

PtycJiochcilus grandis (Ayres) (1/1)
Sites : Skin, gills, fins, mouth, eyes

LIST OF FISHES NEGATIVE FOR PARASITES

(Number of fish examined indicated in parentheses)
Acipenseridae

Acip()is(r mcdirostris Ayres, Green sturgeon (1)
Clupeidae

Dorosoma petcncnsc (Gunther), Threadfin shad (9)
Cottidae

Coitus gulosus (Girard), Kiffle sculpin (1)

FISH PARASITES 207

Cyprinidae

Lavinia cxilicauda exilicauda Baird and Girard, Sacramento hitch (2)

Notcmigonus cnjsolcucas (Mitchill), Golden shiner (3)
Embiotocidae

Ilystcrocarpus iraskii Gibbons, Tule perch (1)
Pleuronectidae

Platichthys stellatus (Pallas), Starry flounder (2)
Salmonidae

Oncorhynclnis isliawytsclia (Walbaum), King salmon (3)

Salmo rya{rfZ7!<?ri Richardson, Rainbow trout (24)

ACKNOWLEDGEMENTS

The authors wish to express thanks and appreciation to John S. Mac-
kiewicz of the State University of New York at Albany for his assist-
ance in the identification of the two caryophyllaeids encountered in this
study; to Gary Bryant, Joseph Silva, A. D. Lyons, and other employees
of the Fish Screen, Tracy Branch, Bureau of Reclamation, Department
of Interior for makint? the facilities available ; and to Norris L. Hensley
and his wife and Shelia Hensley for their assistance in examination of
fish.

REFERENCES

Becker, C. D. 1964. The parasite-vector-host relationship of the hemoflagellate,

Cryptol)ia salmositica Katz, the leech, Piscicola salmosiiica Meyer, and certain

freshwater teleosts. Ph.D. thesis, Univ. Washington. 200 p.
Becker, C. D., and M. Katz. 19G5. Bahcsiosoma Ictragonis n.sp. (Sporozoa: Dac-

tylosomidae) from a California teleost. Joiir. Protozool., 12(2) : 189-193.
CoUey, F. C, and A. C. Olsen, Jr. 1963. Posthodiplostomtim minimum (Trenia-

toda : Diplostomidae) in fishes of Lower Otay Reservoir, San Diego Connty, Cali-
fornia. Jour. Parasitol., 49: 148.
Crane, John, and J. D. Mizelle. 196S. Studies of monogenetic trematodes. XXXVII.

A population study of two species of Ancyrocephalinae on the bluegill in California.

Jour. Parasitol., 54(1) : 49-00.
Davis, H. S. 1947. Studies of the protozoan parasites of freshwater fishes. Fish

and Wildlife Service Fishery Bull., 51(41) : 1-29.
Edwards, Stephen R., and F. M. Nahhas. 1968. Some endoparasites of fishes from

the Sacramento-San Joaquin Delta, Calif. Fish Game, 54(4) : 247-256.
Haderlie, E. C. 1953. Parasites of the freshwater fishes of Northern California.

Univ. Calif. Publ. Zool., 57(5) : 303-440.
Heckman, Richard A. 1974. Parasites of golden trout from California. Jour. Para-
sitol., 60(2) : 363.
Ishii, S. 1934. On a Filaria parasitic in the caudal fin of Carassius auratus L.

from Japan. Proc. 5., Pacific Sci. Cong., 5 : 4141-4143.
Jameson, A. P. 1931. Notes on California Mvxosporidia. Jour. I*arasitol., 18(2) :

59-68.
Kritsky, D. C, and J. D. Mizelle. 1968. Studies on monogenetic trematodes.

XXXV. Some new and previously described North American species of Gyrodac-

lyhis. Amer. Midi. Nat., 79(1 ) : 205-215.
Kudo, R. R. 1920. Studies on Myxosporidia. A synopsis of genera and species of

Myxosporidia. Illinois Biol. INIonogr., 5(3-4) : 1-265.
Leitritz, E. 1960. Trout and salmon culture. Calif. Dept. Fish Game, Fish. Bull.,

(107) : 1-169.
Miller, L. W. 1967. A heavy infestation of the threadfin shad, Dorosojna pete-

nense, by the yellow grub, Clinosiomum marginatum. El Capitan Reservoir, San

Diego County, California. Calif. Fish Game, 53(4) : 293-295.
Miller, Richard L. 1967. Ecology of Posthodiplosfomum minitnum (Trematoda:

Diplostomidae) in largemouth bass of Southern California. M.A. Thesis, San Diego

State College, San Diego. 61p.

208 CALIFORNIA FISH AND GAME

Miller, Ricliard L., A. C. Olson, Jr., and L. W. Miller. 1073. Fish parasites occur-
ring in thirteen Southern California Reservoirs. Calif. Fish Game. r>9(3) : 190-200.
Mizelle, J. D. 19G2. Studies on monogenetic tromatodes. XXII. Dacfylogyrus cali-

fornieitxix sp. n. from the Sacramento squawfish. Jour. I'arasitol., 4S(4) : .".".V.'."?.
Mizelle, J. D., and J. A. Arcadi. 1945. Studies on monogenetic trematodes. XIII.

Urocleidus seculus, a new species of Tetraonchinae from the viviparous top min-
now, Gamhusia affinis affinis (Baird and Girard). Amer. Micr. Soc, Trans.,

65(4) :293-29C.
Mizelle, J. D., and John W. Crane. 19G4. Studies on monogenetic trematodes.

XXIII. Gill parasites of Micropterus nahnoides (Lacepede) from a California

pond. Amer. Micr. Soc., Trans., 83(3) : 343-348.
Mizelle, J. D., and D. C. Kritsky. 19G7a. Studies on monogenetic trematodes

XXXIII. New species of Gyrodactylus and a key to the X^orth American species.

Amer. Micr. Soc, Trans., 8G(4) : 390-101.
. 1907^. Studies on monogenetic trematodes XXXVI. Gyrodactylid para-
sites of importance to California fishes. Calif. Fish Game, 53(4) : 204-272.
Mizelle, J. D., and II. D. McDougal. 1970. Studies on monogenetic trematodes.

XLV. The genus Dactylogyrus in X^orth America. Key to species, host-parasite

and parasite-host lists, localities, emendations and description of D. kritskyi sp. n.

Amer. Midi. Nat. 84(2) : 444-462.
Mizelle, J. D., and C. E. Price. 1964. Studies on monogenetic trematodes. XXVII.

Dactylogyrid species with the proposal of Urocleidodes gen. n. Jour. Parasitol.,

50(4) : 579-584.
Mizelle, J. D., D. S. Stokely, B. J. Jaskoski, A. D. Seamster, and L. H. Monaco.

1956. North American freshwater Tetraonchinae. Amer. Midi. Nat., 55(Ij) : 162-

179.
Mizelle, J. D., R. J. Toth, and H. Wolf. 1961. On the life cycle of Cleidodtscus

pricei Mueller, 1936. Jour. Parasitol.. 47(4) : 034.
Murphy, G. 1942. Relationship of the freshwater mussel to trout in the Truckee

River. Calif. Fish Game, 28 : 80-102.
Noble, E. R. 1943. Nuclear cycles in the protozoan parasite Myxidium gasierostei

n. sp. Jour. Morphl., 73(2) : 281-289.
1950. On a myxosporidian (protozoan) parasite of California trout.

Jour. Parasitol., 36(5) : 457-460.
Price, C. E., and J. D. Mizelle. 1964. Studies on monogenetic trematodes. XXVI.

Dactylogyrinae from California with the proposal of a new genus. Pellucidhapfor.

Jour. Parasitol., 50(4) : 572-578.
Van Cleave, H. J., and E. C. Haderlie. 1950. A new species of the acanthocephalan

genus Octospinifer from California. Jour. Parasitol., 36(2) : 169-173.
Wagner, E. D. 1953. A new species of Proteoccphalus Weinland, 1858 (Cestoda),

with notes on its life history. Amer. Micr. Soc, Trans., 72(4) : 364-369.
Wales, J. 1958. Two new blood fluke parasites of trout. Calif. Fish Game., 44(2) :

125-136.
Wales, J., and H. Wolf. 1955. Three protozoan diseases of trout in California.

Calif. Fish Game, 41(2) : 183-187.
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Calif. Fish and Game 61(4) : 200-214. 1975.

FISH TRAPPING: A NEW METHOD OF EVALUATING

FISH SPECIES COMPOSITION IN LIMNETIC

AREAS OF RESERVOIRS^

LARRY J. PAULSON ^ and F. A. ESPINOSA, JR.^

Department of Biological Sciences
University of Nevada, Las Vegas 89154

Lighted fish traps were suspended in limnetic waters of Las Vegas
Bay, Lake Mead, Nevada to evaluate the fish species components of a
dense scattering layer. Preliminary results suggested that the scattering
layer was composed primarily of young-of-the-year threadfin shad. The
lighted traps appear to be an inexpensive, effective means of sampling
shad in a scattering layer.

INTRODUCTION

Echo sounding results from Las Vegas Bay, Lake Mead, Nevada
revealed a dense scattering layer in limnetic waters. We suspected that
threadfin shad, Dorosoma petenensc (Giinther), comprised a majority
of the scattering layer since they are well established in Las Vegas
Bay (Deacon, Paulson and Minckley 1970), and a series of Clarke-
Bumpus plankton tows through the scattering layer failed to reveal
zooplankton concentrations dense enough to account for the scattering
layer (Deacon and Tew 1973). Netseh, Kersh, Houser, and Kilambi
(1971) identified a similar scattering layer as threadfin and gizzard
shad (Dorosoma cepedianum LeSueur) and described their horizontal
and vertical distribution in Beaver Keservoir, Arkansas by utilizing
echo sounding and a variety of conventional sampling gear. Since we
did not possess elaborate trawling gear we developed an alternative
method of evaluating the scattering layer.

This paper describes a simple and inexpensive method to evaluate
and identify the shad components of sonic scattering layers in limnetic
areas of reservoirs by utilizing lighted fish traps.

DESIGN AND METHODS

Minnow traps have been used successfully in springs, pools, streams,
and ponds (Hedges and Ball 1953; Deacon and Wilson 1967; Hubbs,
Baird and Gerald 1967). Extensive trapping in lakes and reservoirs,
however, is not a common practice. Usually "hoop nets" or other en-
trapment gear are more successful (Bennett 1971). We designed our
traps as a combination of the minnow trap and hoop net (Figure 1).
Each trap was constructed with two circular steel support rods each
3.2 mm (0.13 inch) in diameter enclosed with 6.3 mm (0.25 inch gal-
vanized wire mesh. The traps were 0.9 m (35 inches) long and 1.57 m
(61.8 inches) in circumference with 10 cm (3.9 inches) funnel open-

i Accepted for publication March 1975.

2 Now with the Division of Environmental Studies, University of California, Davis, Cali-

fornia 95616.

3 Now with the U. S. Forest Service, Clearwater National Forest, Orofino, Idaho 83544.

( 209 )

210

CALIFORNIA FISH AND GAME

ings at eacli end of the trap. Eaeli funnel \vas 0.3 ni (11.8 inclie.s) long.
An access hole was cut in the top of each trap to permit removal of cap-
tured fish. The traps were suspended to desired depths by nylon rope
secured to permanently moored, fiberglass buoj's.

Since threadfni shad are positively phototactic (Johnson 1970), we
included a light source inside each trap to attract the shad. A light
package, consisting of two 6-volt, dry cell batteries and a single 6-volt
light bulb, was placed inside a 3.8 liter (1 gal) glass jar. Each jar was

FIGURH 1. Cylindrical wire fish trap used to evaluate threadfin shad populations in sonic
scattering layers.

FISH TRAPPING 211

waterproofed by lining the lid with a rubber seal coated with high
vacuum stopcock grease. This light source provided an estimated 3 m
(9.8 ft) sphere of illumination in Las Vegas Bay water. The jars were
able to sustain water pressures at our deepest sampling depth of 20 m
(65.6 ft). The total cost of materials and labor was $10.00 per lighted
trap.

Test trapping was done to determine : (i) if fish could be captured,
(ii) if differences existed between day and night sets, (iii) if lights
were necessary, and (iv) if a relationship existed between trapping
results and the intensity of sonic recordings. A 48-hour trapping period
was conducted in a limnetic area 61 m (200 ft) deep (Station A). A
single trap was set without lights for 24 hours and with lights for
another 24 hours. The trap was checked at 12-hour intervals. During the
day the trap Avas set at 15 m (49.2 ft) ; at night it was raised to 10 m
(32.8 ft). The trapping depth was determined after observing echo-
grams made just prior to the placement of the trap. The trap was set
at the depth where the echogram indicated a distinct and intense sonic
scattering layer. Echo sounding was done with a Furuno model FM22-
D Echosounder (Konel Corporation).

This trapping period was followed by two more night sets : a single,
lighted trap set at 10 m (32.8 ft) in a limnetic area 90 m (295.3 ft)
deep (Station B), and a vertical series of three lighted traps set at 5,
10, and 20 m (16.4, 32.8, 65.6 ft) at Station A.

Captured fish were immediately preserved in 10% formalin. Total
length (mm) and weight (g) were recorded for each fish and means
computed for each catch.

RESULTS AND DISCUSSION

The trap catches consisted entirely of threadfin shad, except at Sta-
tion A, where six black crappie, (Pomoxis nigromaculatus LeSueur),
were captured at a depth of 20 m (65.6 ft) on 16 and 17 September
(Table 1). Threadfin shad can be captured in limnetic areas, but only
at night, with lighted traps. Day sets were unsuccessful with or with-
out lights. Netsch et al. (1971) found substantial differences between
day and night midwater trawl captures of shad. They attributed this
difference primarily to a more dense, uniform distribution at night as
opposed to scattered schools during the day. Our echograms revealed a
somewhat similar pattern of night distribution (Figure 2-lA) ; how-
ever, several schools were observed during the day (Figure 2-lC), and
a decrease in population density was not apparent. Apparently trap
avoidance was the main reason for unsuccessful daytime captures.
This is the major drawback of trapping ; only night collections are suc-
cessful. Costly sampling gear such as a midwater trawl would have to
be used if information on daytime distribution was required.

The catch results from the vertical trap series at Station A on Sep-
tember 16 and 17 indicate that shad population densities are sharply
stratified. This stratified catch pattern corresponds satisfactorily with
the intensity of the scattering layer at the 5 and 10 m (16.4 and 32.8
ft) depths. However, the relationship at the 20 m (65.6 ft) depth is
not evident. The echogram (Figure 2-lB) revealed that a secondary
layer of fish was present at 15 and 20 m (49.2 and 65.6 ft) yet only 26

212

CALIFORNIA FISH AXD GAME

0.
liJ

5
1 0

1 5

2 0
2 5

3 0-

3 5

4 0

4 5

FIGURE 2.

5 0

5 5

Representative Sonar echograms taken at Station A, Las Vegas Bay, Lake Mead,
Nevada on September 4 and 5 (lA and IC) and September 16 and 17, 1972
(IB), shovi^ing the typical scattering layer encountered during various hours of
the day. Column heads indicate the beginning of the 12-hour sampling period.

FISH TRAPPING

213

Mean weight
of shad

(gm)

1 CO 1 t^ O O O
1 1 ^ 1 lO O) t>. i-t
1 1 . 1 ... .
Ill »— (

E
0

Mean length

of shad

(mm)

1 1 CO 1 lO O O CO

1 1 »0 1 0> O ^^ 05
1 1 CO 1 CO •>* •>!• CO

Number of
fish captured

OO'^OcO'Ttit-.CM

'-' t~ IN r^ CO

.-1 CO

e
'SL

J3 ^
Si

©•noino'coo

1-1 1-C rH rt ,-1 >-l <N

H
X

£
1

'►3

•••
0
w

'k
«

2000-0800
0800-2000
2030-0830
0830-1930
2000-0800
1900-0700
1900-0700
1900-0700

M
«

(NINNNIMIMMC^

O) 05 05 05 0)05 0 05

aaaacaao.
mmmmmmmm

c
o

A 3-4

A 4

A 4-5

A 5

B 5-6

A 16-17

A 16-17 -.

A 16-17

a
■d

CD
(N

214 CALIFORNIA FISTT AND fJAMF,

shad -were captured. Shad in Las Vegas Bay undergo a diurnal, vertical
migration (Deacon and Tew 1973). After sunset they began to ascend,
and at total darkness the majority of the shad occupy Avaters between
10 and 15 m (32.8 and 49.2 ft). During the early morning tliey form
schools and most descend to depths of 15 and 20 m (49.2 and Go. 6 ft).
Since the echogram for the trap period was recorded at 1700 hours,
just prior to darkness and completion of the shad migration, we suspect
the shad were not exposed to the traps long enough to capture sub-
stantial numbers.

Evaluation of mean lengths and weights showed that all captured
shad were young-of-the-year (Table 1). It is difficult to judge the
effectiveness of the traps for capturing larger shad and other fish
species. Obviously, the 10 cm (3.9 inch) funnel openings in the traps
Avould limit the capture of larger species if they were present in the
scattering layer. Vertical gill nets set at Station A 2 weeks prior to
the trapping failed to capture predatory species or larger shad within
the scattering layer (Deacon and Tew 1973). This suggests that the
traps were effectively sampling the scattering layer. Adult shad may
avoid the traps, or they may not be present in limnetic areas. Johnson
(1970) noted diurnal and seasonal segregation between young and
adult shad. Summer midwater trawl collections in Lake Mead revealed
that young-of-the-year shad predominated in limnetic areas, whereas
electrofishing in littoral areas resulted in capture of adult shad.
(Deacon et al. 1970). We therefore assumed that the traps were
sampling a representative portion of the limnetic shad poi)ulation.

Despite the very limited sampling, the trapping method appears to
have some merit in evaluating the shad components of sonic scattering
layers in the limnetic areas of reservoirs. With further research the
trapping could perhaps be utilized in estimating relative abundance
and investigating distributional patterns of threadfin shad.

REFERENCES

Bennett, G. AV. 1971. Management of lake.s and ponds. Van Xostrand lieinliokl Co.
New York, New York. 375 p.

Deacon, J. E., and P.. L. Wilson. 10G7. Daily activity cycles of Crcnichlhi/s haileyi,
a fish endemic to Nevada, Sonthwest. Nat., 12(1) : 31-14.

Deacon, J. E., L. .T. Tanlson, and C. O. ISIinckley. 1070. Effects of Las Vegas Wash
efflnents ni)on l)ass and other game fish reproduction and success. T'niversity of
Nevada, Las Vegas, Dingell .Tohnson Project, Nevada F2(). Segment 0 Jol) Comple-
tion Report. OS p. (mimeo) .

Deacon, J. E., and R. AV. Tew. 1973. Intcrrelationsliips l)etween chemical, physical
and biological conditions of the waters of Las Vegas I?ay of Lake Mead. University
of Nevada, Las Vegas. Final Ileport to Las Vegas Valley Water District. 186 p.
(mimeo) .

.Tohnson, J. E. 1970. Age, growth, and population dynamics of threadfin shad,
Dorosoma pclcnense (Giinther), in Central Arizona reservoirs. Amer. Fish. Coc,
Trans., 99 (4) : 739-753.

Hedges, S. P.., and R. E. Pall. 1953. Production and harvest of bait fishes in
Michigan. :\Iichigiin Department of Conservation. Institute for Fisheries Research,
Ann Arbor, Michigan. Misc. Pub. No. G. 29 p.

Knbbs, C, R. E. Baird, and J. W. Gerald. 19G7. Effects of dissolved oxygen concen-
tration and light intensity on activity cycles of fishes inhabiting warm springs. Amer.
Mid. Nat.. 77 (1) : 104-115. .

Netsch, N. F., G. M. Kersh, .Tr., A. Ilonser, and R. V. Kilambi. 1971. Distribution
of young gizzard and threadfin shad in Beaver Reservoir. 95-105 in Gordon E. Hall,
ed." Reservoir fisheries and limnology. Spec. Pub. No. Amer. Fish. Soc, 8, Washing-
ton D.C.

Calif. Fish and Game 61 (4) : 215-227. 1975.

ASPECTS OF THE LIFE HISTORY OF TRESUS
NUTTALUI IN ELKHORN SLOUGH^

PATRICK CLARK 2, JAMES NYBAKKEN and LAWRENCE LAURENT ^

Moss Landing Marine Laboratories, Box 223, Moss Landing, Cal. 95039

A 2-year study of the reproductive cycle and growth rate of the gaper
clam, Tresus nuttallii, in Elkhorn Slough indicated that the primary spawn-
ing time is from February to April, but that some reproduction probably
occurs during every month of the year. Based on remeasurement of
individually marked clams, a growth curve for clams up to 55 mm
(2.2 inches) in shell lengths was also established.

INTRODUCTION

In Elkhorn Slough the gaper clam Tresus {■= Schizoihaems) nut-
tallii (Conrad), is an important sport species that is fished heavily
during periods of spring tides. Detailed knowledge of the reproductive
cycle and growth rate of the gaper clam are presently lacking, and it
is the purpose of this paper to report the results of a 2-year study of
the reproductive cycle and growth rate of T. nuttalliiin Elkhorn Slough,

Previous studies concerning the reproductive cycle in the genus
Tresus have concerned Tresus capax (Gould), a more northern species,
with the majority of its populations found above Humboldt Bay, Cali-
fornia (Swan and Finucane 1952). Winter spawning of T. capax
has been reported by Swan and Finucane (1952) for the populations
on the coast along the San Juan Archipelago, by Reid (1969) for
those on the coast of British Columbia, Canada, and by Machell and
De Martini (1971) for the population in Humboldt Bay, California.
As yet nothing has been published concerning the growth rate of either
T. nuttallii or T. capax.

MacGinitie (1935) warned that the heavy clamming pressure en-
dured by the many species of game clams in Elkhorn Slough might
lead to the local extinction of these game species. We found that three
of the bivalve species that MacGinitie counted as common or abundant
{Protothaca staminea, Saxidomus nuttallii and Clinocardinium nat-
talli) can no longer be considered common.

METHODS AND MATERIALS

Spawning Cycle Study

A minimum of 10 and a maximum of 24 Tresus nuttallii above 90 mm
(3.5 inches) in length (greatest posterior-anterior dimension) were
collected during each series of davlight tides lower than —0.7 ft
(—0.2 m) from a mudflat in Elkhorn Slough (lat 36°48'36"N; long
121°47'6"W). Collecting was done by shovel. The clams were brought
into the laboratory where their lengths and widths (greatest lateral
dimension) were measured to the nearest mm with vernier calipers. The

1 This study was supported by the California Department of Fish and Game through

Contracts 6S-1401 and 6S-1414 to the Moss Landing Marine Laboratories. Accepted

March 1975.
- Present address, Department of Zoology, University of New Hampshire, Durham,

New Hampshire.
3 Present address. Department of Fish and Game, 2201 Garden Rd., Monterey,

California.

(215)

216

CALIFORNIA FISH AND GAME

soft parts were preserved in 10% buffered formalin. Gonadal blocks
were dissected from the dorso-posterior area of the fixed body, de-
hydrated and infiltrated by the dioxnno-paraffin method of (laligher
and Kozloff (1964), embedded in i)araffin, sectioned at 7/x intervals,
and stained with standard hematoxylin and eosin procedures (IIu-
mason 1967).

FIGURE 1. Sections of gonad tissue of female Tresvs nutiallii. A, inactive phase (4X); B,
early active phase of oogenesis (10 X). Photographs by Pat Clark.

GAPER CLAM

217

Upon examination of tlie {gonadal preparations, each individual
adult female sampled was placed into one of the five developmental cate-
gories established by Ropes and Stiekney (1965) in their study of
Mya arcnaria: i) inactive; ii) active; iii) ripe; iv) partially
spawned; and v) spent. The inactive phase was characterized by col-

If^.-iji^

^i^ ^^. XI

FIGURE 2. Sections of gonad tissue of female Tresus nuftaUii. A, late active phase (4X); B,
ripe phase of oogenesis (4X). Photographs by Pat Clark.

218

CALIFORNIA PISH AND GAME

lapsed follicles uith few to no oo^onia i)i-eseiit (Fijiure lA). In the
early active i)liase the follicle wall began to thicken witli the follicle
cells beginninj^ to form oogonia (Figure IB). In the late active phase
the alveolar wall was thin, the oogonia elongate, at wliidi lime they
were considered primaiy oocytes, and the oocytes were attached to the
alveolar wall by means of stalks (Figure 2A). AVhen there were more

m. ft

.: V

^ y

• • ♦.

FIGURE 3. Section of gonad tissue of female Tresus nuttallii. A, partially spawned phase
(4X); B, spent phase of oogenesis (lOX). Photographs by Pat Clark.

GAPER CLAM 219

oocytes lying freely within the lumen than were attached to the al-
veolar wall, the ovary was considered to be in the ripe phase of develop-
ment (Figure 2B). In the partially spawned phase, the alveoli were
partially empty and the follicle wall was slightly thickened (Figure
3A). The spent phase was characterized by inflated follicles with
degenerating residual oocytes and debris (Figure 3B).

Since it is impossible to distinguish inactive females from inactive
males, the number of specimens in the inactive state were divided in
half and the resulting quotient was used as the number of inactive
clams. Laurent (1971) found that within his samples the ratio of males
to females was 1:1 (P == .95, Chi Square Test). This ratio was as-
sumed to exist in the samples obtained for this study.

The population density of juvenile clams less than 75 mm (3 inches)
in length was measured during each series of daylight tides lower than
—0.7 ft (—0.2m) in the five sites of the mudflat sampled for adults.
Densities were determined to test for correlations between the number
of juveniles settling and the gonadal condition of the mature popula-
tion. From each of five sites on the mudflat a sample of 0.15 m-
(1.6 ft-) was chosen and excavated to a depth of 12 cm (4.7 inches).
The substrate within the samples was sieved through a 2-mm (0.08-inch)
mesh sieve. The residue was then taken to the laboratory where all the
live Trcsus were removed, measured with vernier calipers to the nearest
0.1 mm (0.004 inch) and a frequency distribution and histogram
constructed.

Growth Rate Study

There are at least two possible methods of determining growth in
bivalves: i) by following a size class through time; or 2) by repetitive
measurements of an individually marked population. Laurent (1971)
attempted the former method and was not successful in estimating
growth ; nearly continuous recruitment prevented the following of one
size class through time. The latter method was started by us in Febru-
ary 1971 on an experimental basis.

Initially, we took juveniles collected from the juvenile population
study, measured them to the nearest 0.1 mm (0.004 inch) and planted
them in two plastic buckets located subtidally in Elkhorn Slough. We
retrieved the buckets 50 days later on March 2, 1971. Since we had not
marked the juveniles, we were unable to determine anything but mean
growth in each bucket. These juveniles were then individually marked
with printed numbers attached to the right valve and the numbers were
covered with Dekaphane. The buckets with their marked juveniles were
returned to their racks on March 25, 1971. They w^ere then retrieved
May 18, June 12, September 15, and November 3, 1971. Three more
plastic containers were placed subtidally in the slough on June 14,
1971 to make a total of five containers w^ith marked, premeasured juven-
iles. "When the containers were retrieved the clams were remeasured
and those that had died were replaced with freshly collected juveniles.
The containers were returned to their subtidal racks. Sometime in
December, 1971, all of the containers were overturned and the contents
lost. In March 1972, two racks of much sturdier construction were
placed in the slough (Figure 4).

220

CALIFORNIA FISH AND GAME

sand

anchor

FIGURE 4. Subtidal rack for growth studies of Tresus nuifallii.

The new subtidal growth racks utilized four 1.8-m (6-ft) fence an-
chors buried into the slough bottom approximately 0.6 m (2 ft). To
these fence anchors were attached two 0.9-m x 1.2-m (3-ft x 4-ft) sheets
of plywood which were sealed with finishing resin. The uppermost sheet
of plywood contained fifteen 12.7-cm (5-iuch) diameter holes tlirough
which were placed 10.2-cm (4-inch) diameter PVC (polyvinyl chloride)
pipes 0.9 m (3 ft) in length. One end of each PVC pipe was sealed by
means of a sheet of rubber and a hose clamp. The pipes were filled with

GAPER CLAM 221

sediment wliicli was obtained either from beach sand that had been
sieved to remove most of the organic debris or from the slough bottom.
At least one gaper clam was placed in each pipe, and the juveniles were
placed in smaller diameter PVC pipes that then Avere placed within
the larger pipe.

Each clam was removed from the rack at intervals depending on the
clam's size: i) those less than 10 mm (0.4 inch) were measured at
1-week intervals; ii) those between 10 and 50 mm (0.4 and 2.0 inches)
were measured at 1-month intervals; and iii) those greater than 50 mm
(2.0 inches) Avere measured at 3-month intervals. A graph of length
versus time in days was constructed for each clam. This line was then
resolved into points with each point representing 1 day along the
growth line. Size classes were then chosen with the class interval being
5.0 mm (0.2 inch). All the points that fell within each size class were
combined. A regression analysis was conducted on the points within
each size class to obtain a line for each size class. These lines were then
connected end to end in a progressive order of size starting from the
smallest measured individual and progressing to the largest measured
individual. From this procedure a non-smooth growth curve was ob-
tained. The curve was then analyzed by means of a curvilinear
regression analysis to obtain a smooth curve (Figure 5). All the com-
putations were done on a Wang 700 Series Advanced Programming
Calculator.

RESULTS

Gonadal sections of adult Trcsus nuttallii have been examined from
specimens collected during the period from February 1970 to June
1972. Measurements on those specimens obtained between February
1970 and December 1970 were data obtained from Laurent (1971).

222

CALIFORNIA FISH AND GAME

r-
O

— I—

(uiui) M46ua~|

— i-
o

o
o

o
in
ro

O ^

ro «

9 •

in at

CO <

O
O
CM

o
o

o
in

FIGURE 5. Growth curve for Tresus nuffallii from Elkhorn Slough, California.

GAPER CLAM

223

Only females were considered in this study. Males were not considered
due to tlie difficulty of determining their state of gonadal development.
Samples were not taken during the months of September 1970 and
September and October 1971 because there were no tides below -0.7 ft.
(-0.2 m) during daylight hours. Juveniles and adults were collected
during the months of February and March 1972 for the growth rate
study. Since these specimens were to be kept alive no spawning cycle
data were obtained.

The gonadal condition of female clams sampled between February
1970 and June 1972 indicated that the primary time of spawning in
1970 was the winter and spring (Figure 6). In 1971, clams were found
spawned out again in February but also in June (Figure 7). In 1972,
spawned clams were found in all months checked (Figure 8). One
problem with these data is that for many sampling months the sample
size is too small to warrant making definitive statements.

roo

EG-

S 50'
a.
40-

30-

20-

m t^

Jan Ftb Morch April Moy Juni July Aug Stpl Oct Nov 0«c

1970 Moniri

L«g*nd for gonod condition r-^vN moctivo, iiNiu octivo,
^^S rip*, ^sap«tJolly vowtod, cnzitpont

FIGURE 6. Gonad condition of female gaper clams collected from Elkhorn Slough in 1970.
The length of each shaped area represents the percentage of clams in each
gonadal condition. N = number of females sampled.

100

80-

70-

60-
c
5 50

6 4 I

^ E:

Jon

Fob

Morcli April Moy Juno July Aug SopI

1971

Monlli

Ltgtnd for gonod conditions t^l^ moctivo, ^SSoetlvt
^^npo, EKSportiolly ipdwnod, cr^ntfM

FIGURE 7. Gonad condition of female gaper clams collected from Elkhorn Slough in 1971.
The length of each shaded area represents the percentage of clams in each
gonadal condition. N = number of females sampled.

224

CALIFORNIA FISH AND GAME

Those data available on the density of juveniles suggest that some
settling occurred during every month in the sampling period from
April 1971 to June 1972. Very definite peaks were noted during May
1971 and April 1972 (Figure 9^

100-

90-
80-
70-

60-

fc 50
a.

40-
30-
20-

10-

Jan Feb March April

1972 Month

May

June

Legend for gonad condition: l^^ inactive, l-H+HJ active,

ripe, E^s partially spawned,

spent

FIGURE 8. Gonad condition of female gaper clams collected from Elkhorn Slough in 1972.
The length of each shaded area represents the percentage of clams in each
gonadal condition. N = number of females sampled.

GAPER CLAM - 225

150

100

«
E

50-

• April May June July Aug Sept Oct Nov Dec Jon Feb March April May June

1971 1972

Montli

FIGURE 9. Total number of juveniles 2 to 4.9 mm collected each month per m ^.

Growth Rate Study

The gaper clams placed in the subtidal growth racks ranged in size
from 2.2 to 143 mm (0.07 to 5.6 inches) in length. A growth curve was
compiled for those claims between 2.2 and 55 mm (0.07 and 2.2 inches).
When this curve was smoothed by means of a curvilinear regression
analysis, it fit the equation : Length (mm) = 0.0027 + 0.2043 (age in
days) — 0.0002 (age in days)2, (Standard Error = 0.41) (Figure 5).

Those clams greater than 55 mm (2.2 inches) in length were not in
the subtidal racks long enougli to provide enough data to extend the
curve. It is apparent from this study that adult gaper clams, greater
than 75 mm (3 inches) in length, should remain in racks for at least a
year to obtain a complete growth curve.

DISCUSSION

The gonad sections for the period from February 1970 to June 1972
suggest that the primary spawning period for gaper clams in Elkhorn
Slough is from February through April. This is inferred from the high
fraction of females that are ripe, partially spawned, or spent at this
time. The juvenile density study indicates high numbers per m~ of
newly settled gaper clams 2 to 4.9 mm (0.08 to 0.2 inch) during May
1971 and April 1972. There appears to be approximately a 1-month lag
between spawning as determined from the gonad sections and the ap-
pearance of a high peak of newly settled juveniles in the samples.
Fifty percent of the adult females sampled in April 1971 w^ere in a
ripe condition and all the females sampled in May 1971 were in an
active condition (Figure 7). This change in gonadal condition indicates
that spawning occurred between the two sampling dates. The juvenile
density data indicate that there was a peak in juvenile settling in
May 1971 and a decline in June 1971 (Figure 9).

The point of intersection of the abscissa and ordinate of the growth
curve (Figure 5) is that point where the veliger begins forming a cal-
cium carbonate shell and settles. Since the actual data begin at 2.2 mm
(0.08 inch), the growth curve was extrapolated back to zero using the
growth equation. This procedure indicates that it takes approximately

226 CALIFORNIA FISH AXD GAME

10 days from settling in order to grow to a size of 2 mm (0.08 inch)
and 25 days in order to grow to a size of 5 mm (0.2 inch). Loosanoflf
(1963) states that most temperate bivalves have a maximum larval life
of 30 days. If this is true for the gaper clam in Elkhorn Slough, then
spawning would have occurred from 40 to 45 days prior to the ob-
served peaks. Judging from the dates at which the two above mentioned
samples Avere collected, we would predict a larval life of 21 to 30
days for the gaper clam in Elkhorn Slough.

The work done by Machell and De Martini (1971) on Trcsus capax
in South Humboldt Bay closely parallels this study. We both deter-
mined that the primary spawning period is in the late winter, from
January to April for Ti'csus capax, and from February to April for
T. nuttaUii Machell and De Martini found that the active phase was
associated with the highest temperature and salinity measurements and
spawning with the seasonal low values for these parameters. We believe
that the active phase is associated with the initial loAvering of the water
temperature, and spawning with the seasonal low temperature (Figures
6 and 7). Machell and De Martini found spat only during the spring,
whereas we found spat throughout the Avhole year.

The reasons for the observed differences are probably many, not the
least of which is that we are dealing with different species. One possible
clue as to the differences in spat settling times could be the large ranges
of water temperatures found each day in Elkhorn Slough. For example,
on February 27, 1971 the water temperature varied over a 24-hr period
from 9.6 to 13.4 C (42.9 to 56.1 F) and during August 16, 1971 it
varied from 13.2 to 19.2 C (55.8 to 66.6 F). The temperature range for
August 16 is noteworthy since it falls within the range of daily water
temperatures recorded during the spawning season. Perhaps, the wide
daily fluctuations in water temperature in Elkhorn Slough explain the
presence of ripe females and newly settled spat in the population
throughout the year; temperatures sufficiently low to trigger spawning
may occur during a number of seasons in Elkhorn Slough. If the daily
temperature ranges in Humboldt Bay are smaller, the difference in
spawning behavior between the two Ti^csus populations might be ac-
counted for.

The growth curve (Figure 5) can be used to estimate clam length
at a given age. A gaper clam 1 year old will be 49.5 to 50.3 mm (1.95
to 1.98 inches) in length 95% of the time, at least in Elkhorn Slough.
Gonadal sections demonstrate that female gaper clams greater than 70
mm (2.8 inches) have mature ova. The growth curve indicates that age
at maturity for a female gaper clam or age of a 70-mm (2.8-iiich) in-
dividual is at least 2 years.

The method used to determine growth rate of the gaper clam in Elk-
horn Slough has not been previously reported. Until now there have
been two options for determining growth : i) a growth model, i.e.
standard exponential curve; or ii) a number of specimens observed
from birth over a long time period. With the method described in
this paper it is possible to obtain an accurate growth curve for an
average individual of a population in 2 years, the only requirement
being that the animal add length, width or height with age.

GAPER CLAM 227

The present study also provides some data on year to year fluctua-
tions in recruitment. The population density study (Figure 9) indicates
that recruitment during 1972 was more than twice as great as the
recruitment during 1971. If there are no catastrophic occurrences on
the mudflats of Elkhorn Slough, 1975 should be a good year for
harvesting gaper clams.

REFERENCES

Galigher, A., and E. N. Kozloff. 1964. Essentials of practical microtechniques.

Lea and Febiger, Philadelphia. 484 p.
Humason, Gretchen. 1967. Animal tissue techniques. W. II. Freeman and Co.,

San Francisco. 569 p.
Laurent, Laurence L. 1971. The spawning cycle and juvenile growth rate of the

gaper clam, Tresus nuttallii, of Elkhorn Slough, California. Master's Thesis, San

Francisco State University. 55 p.
Loosanoff, Victor L., and Harry C. Davis. 1963. Rearing of bivalve molluscs,

p. 1-13G. In Advances in Marine Biology (Vol. 1). Academic Press, London and

New York. 410 p.
MacGinitie, George E. 1935. Ecological aspects of a California marine estuary.

Amer. Midi. Natur., 16(5) : 629-765.
Machell, John R., and John D. De Martini. 1971. An annual reproductive cycle of

the gaper clam, Tresus capax (Gould), in south Humboldt Bay, California.

Calif. Fish Game, 57(4) : 274-282.
Reid, Robert G. B. 1969. Seasonal observations on diet, and stored glycogen

and lipids in the horse clam, Tresus capax (Gould 1850). The Veliger, 11(4) :

378-381.
Ropes, John W., and Alsen P. Stickney. 1965. Reproductive cycle of My a ar en-
aria in New England. Biol. Bull., 128(2) : 315-327.
Swan, Emery Frederick, and John H. Finucane. 1952. Observations on the genus

Schizothaerus. Nautilus, 66(1) : 19-26.

Calif. Fish and Game 61 (4) : 228-232. ]97n.

NOTES ON THE EXTERNAL PARASITES OF
CALIFORNIA INSHORE SHARKS

INTRODUCTION

Specimens and data collected since 1970 from over 900 sharks
captured in San Francisco and Tomalcs Bays indicate that at least two
species of pandarid copepods, Panclaris hicolor (Figure 1) and Pcris-
sopus ohiongatus (Figure 2), occur frequently. Both of these parasites
occur regularly on leopard sharks, Triakis scmifasciafa, and brown
smoothliounds, 3Iustchis Junlci. Between October 1973 and April 1974,
30.0% of the 206 leopard sharks collected hosted either one or both of
these parasitic copepods.

The percentage of Leopard sharks hosting these copepods varies
drastically from catch to catch, season to season and between popula-
tions. Of the 31 leopard sharks examined in October 1973, 61.3%
hosted one or both of these parasites. In April 1974, only 7.5% of the
67 sharks examined hosted these copepods.

While we have not yet found Pcrissopus ohiongatus on other inshore
sharks, we have found Pandaris hicolor on soupfin, Galcorhinus zyop-
terus, sevengill, Notorliynchus maculaius, and spiny dogfish, Squalns
acanthias. We have not examined enough soupfin, spiny dogfisli and
sevengill sharks to determine whether these parasites occur as regularly
as they do on leopard sharks. Pandaris hicolor is approximately 1 cm
(0.4 inch) in length, while Pcrissopus ohiongatus is about 5 mm (0.2
inch in length.

FIGURE 1. Three female Pandaris hicolor (1 cm body length) with elongated egg sacs seen
on the left pectoral fin of a leopard shark. Photo by author.

(228 )

NOTES

229

FIGURE 2. A female Perissopus oblongatus (5 mm bod/ length) with elongated egg sacs
seen on the left pectoral fin of a leopard shark. Photo by author.

Prior to 1967, Pandaris hicolor had been reported only on spiny dog-
fish from European waters (Cressey 1967). Subsequent to this report,
specimens of this species were collected from California waters, but
data on these collections were not published (Cressey pers. comm.). The
report of Pandaris hicolor and Perissopus ohlongatiis on the sharks
mentioned represents a new host-parasite record.

Both of these pandarid copepods are normally found attached to the
fins and dorsal surface of the fish's body. They occur most often above
the gill openings, around the head, and on the trailing edges of fins.
They occasionally occur in small numbers away from the edges of the
pectoral and pelvic fins. The frayed edges of the dorsal fins often sup-
port large numbers of either or both of these parasites. On October 19,
1972, we found 31 Perissopus ohlongatus attached on opposite sides of
the first dorsal fin of a 109-em (43-inch) female leopard shark.

A third pandarid copepod, Echthrogalcus coleoptratus, has been re-
ported from a large variety of pelagic sharks including blue sharks,
Prionacc glauca. It occurs on the body and fins of leopard sharks but
is less noticeable than either of the other two pandarid copepods.
Echthrogalcus coleoptratus is approximately 1 cm (0.4 inch) total
length.

A fourth copepod, Lerncopoda scylicola (Lerneopididae) (Figure
3), was found during our investigations on a single leopard shark and
a single skate, Baja hinoculata. It was previously known to occur only
on sharks of the genus Scyllium (Cressey pers. comm.), which has since
been divided into several new genera. This parasite is apparently rare,
since we have encouilterod it only on these two occasions. In each case,
they occurred in large numbers about the head region.

We have not yet found any parasitic copepods in the buccal cavity
or on the gills probably because our examinations of these organs has
been superficial. Other species of copepods might exist in these areas on
estuarine sharks.

230

CALIFORNIA FISH AND GAME

FIGURE 3. A female Lerneopoda scy/ico/o (4 mm body length) with oblong egg sacs,
by Don Wilson, East Bay Regional Park District.

Photo

While there are several marine leeches that are known to occur on
fishes, only one appears to be common on the elasmobranchs of Tomales
and San Francisco Bays. This leech, BranchdUon lohata (Piscicolidae)
("Figure 4), was originally described by Moore (1952). At that time it
was reported from big skates, brown smoothliounds, spiny dogfish, and
Pacific angel sharks, Squatina calif ornica. It was reported that a few
specimens were taken from the gills of a spiny dogfish, but this was the
only reference to point of attachment (Moore 1952).

AVe have collected BranchdUon lohata from the claspers, buccal cavi-
ties and fins of leopard, brown smootlihound, dogfish, sevengill and
soupfin sliarks. On five occasions BroncJicJlioii lohata was found at-
tached directly to the surface of the eyes of spiny dogfish. In each case,
the area above the eye W'as abraded and inflamed. What connection
there is between the condition of the eyelid and the presence of the
leech on the eye itself is not known. They often occur in numbers of a
dozen or more on the claspers of host sharks. Of the 206 leopard sharks
collected between October 1973 and April 1974, 10.6% hosted this leech.

However, like the copejiods, the ])ercentage of leopard sliarks hosting
BranchcJlion leeches varies from catch to catcli and season to season and
probably among different groups of leopard sharks. Of the 31 leopard
sharks examined in October of 1973, 3.2% hosted this leech. In Janu-

NOTES

231

ary of 1974, 24.4% of the 45 leopard sharks examined hosted this leech.
Branchcllion lohata reaches lengths of 3-4 cm (1.5 inches). Young
leeches are quite prevalent during the summer months. The report of
this leech on leopard, sevengill and soupfin sharks represents a new
host-parasite record.

FIGURE 4. Branchellion lobafa (3 cm total length). Photo by Don Wilson, East Bay Regional
Park District.

232 CALIFORNIA FISH AND GAME

Questions concerning the length of time of attachment to the host,
seasonality of occurrence, effect on sperm injection into the female
shark when attached to claspers, and the general biology of this leech
are largely unknown.

On one occasion we found circular scars or depressions of approxi-
mately 3-4 mm (0.2 inch) on the belly of a leopard shark. Whether or
not these were previous points of attachment for leeches or copepods
is not clear. However, because the leo{)ard shark frequently rests on
the bottom, the belly would be a difficult area to maintain a hold for
any external parasite.

ACKNOWLEDGEMENTS

I am indebted to Roger Cressey of the National Museum of Natural
History for his generous assistance in identifying the copepods and
providing me with taxonomic information, and to Eugene M. Burreson
of Oregon State University for his assistance in the identification of the
leeches.

REFERENCES

Cressey, Roger F. 1967. Revision of the family Pandaridae (Copcpoda: Cali-

goida). U.S. Nat. Mus. Proc, 121 (3570) : 1-133.
Moore, J. Percy 1952. New Piscicolidae (leeches) from the Pacific and their

anatomy. Bernice P. Bishop Museum Occas. Papers, 21 (2) : 1—44.

— Ronald A. Russo, Resident Naturalist, East Bay Regional Park Dis-
trict, 11500 Skyline Blvd., Oakland, California 94619. Accepted
March 1975.

NOTES 233

AN EXTRAUTERINE FETUS IN THE STELLER
SEA LION, EUMETOPIAS JUBATA

On 27 June 1972, we discovered a dead female Steller sea lion on
the beach 2.4 km (1.5 miles) south of Moss Landing Harbor, Monterey
Ba}^, California. The carcass contained one fetus in utero and one
extrauterine fetus in the abdominal cavity. This anomalous condition
lias not been previously reported in a Steller sea lion and as well as Ave
can determine this is the first record of an extrauterine fetus in the
order Pinnipedia.

The fetus in utero measured 740 mm (29.1 inches) from nose to tip
of tail and weighed 12.5 kg (27.5 lb). The extrauterine fetus measured
900 mm (35.5 inches) and weighed 16.0 kg (35.2 lb). Both fetuses were
males and appeared to have full-term development. However, they were
smaller than 22 newborn Steller pups measured by Mathisen et al.
(1962) that ranged between 889 mm (35 inches) and 1219 mm (48
inches) from nose to tip of tail and weighed between 19.0 kg (42 lb)
and 21.8 kg (48 1b).

The female's uterus was not ruptured, indicating that the extrauter-
ine fetus probably arose from an ovum that became fertilized in the
peritoneal cavity. It was not possible to determine the exact site of
implantation of the zygote. At the time of examination the placenta
was not attached to the female but the ventral surfaces of the gastro-
hepatic ligament, duodenum, and lesser curvature of the stomach were
highl}^ vascularized and probably were sites of placental attachment.
Sea lions have a zonary type of placenta that typically forms a band
around a fetus' abdomen and judging from the extrauterine fetus' posi-
tion in the female's abdominal cavity, it is probable that the placenta
was also attached to the female's abdominal wall.

The extrauterine fetus was lying stretched out longitudinally in the
abdominal cavity between the female 's viscera and abdominal wall. The
fetus' back was against the female's parietal peritoneum while its head
was pressed deeply into the diaphragm and its hind feet were lying
against the fetus in utero. The embryonic membranes of the extrauter-
ine fetus were ruptured and the zonary placenta was not around the
fetus in the typical position but was wrapped around its feet, free of
maternal attachment. The placenta may have been torn loose from its
attachment by fetal movements or possibly by pounding of the surf
on the carcass.

The cause of death of the female could not be determined. She showed
no signs of injury and appeared to have been in good physical condition
prior to death. Death may have resulted as a consequence of the
extrauterine fetus although in some mammals extrauterine fetuses
apparently can be carried indefinitely as mummified carcasses (Wil-
liams 1950; Evans and Griffith 1972).

Alio Nuevo Island, approximately 64 km (40 miles) north of Moss
Landing, is the nearest Steller sea lion breeding site. Because most
pups are born in June and early July on Afio Nuevo Island (Orr and
Poulter 1967; Gentry 1970), the female may have died at sea while
enroute to the rookery and was carried ashore by the wind and currents.

234 CALIFORNIA FISH AND GAME

REFERENCES

Evans, J., aiid K. E. Griflitli, Jr. 1!l7l'. Koiirodiictixi' ainim.ilit's in lilacU-tailcd

jackral)l)its. J. Mammal., 53(1) : 192-194.
Gentry, K. L. 1970. Social lu-havior of the Sifllcr sea Hdh. rii.l». tliosis. T'niv.

Calif., Santa Cniz. 113 p.
Mathi.sen, (). A., 1{. T. I'.aadi', and K. J. ]a)\>\<- liMJL'. lireodin^,' liahits, -rowtli.

and stomach contents of the Steller sea lion in Alaska. J. Mammal., 43(4):

469-477.
Orr, R. T., and T. C I'onlter. 19G7. Some observations on reproduction, growth,

and social behavior in the Steller sea lion. ("alif. Acad. Sci. I'rcK'., 35: 193-2120.
AVilliams, W. L. 1950. The diseases of the fjenital or;,'ans of domestic animals.

Ethel Williams I'limpton I'ubl., Worcester, Mass. 050 p.

— Larry G. Talent and Carlinc L. Talent, Moss Landing Marine Lahor-
atorics of the California State Universities, Moss Landing, California
95039. Accepted March 1975.

NOTES

235

ANOMALOUS OTOLITHS FROM THE NORTHERN
ANCHOVY, ENGRAULIS MORDAX

The Fish and Game Commission authorized taking anchovies for
reduction to fish meal in 1965. The Department lias sampled the reduc-
tion fishery landings for both age and size composition of catch. By the
end of the 1971-72 season, over 22,000 otoliths had been collected for
determining age composition of the catch. There has been a number of
anomalous otoliths observed in these collections. Collins and Spratt
(1969) described opaque and translucent otoliths, two of the more
frequently occurring anomalies. These types have been present through-
out the fishery and make up an estimated 5% of all otoliths taken.

FIGURE 1. Otolith types from one year old anchovies: A. normal, B. narrow, C. oval.
Photograph by Jack W. Schott.

236

CALIFORNIA FISH AXD OA^ME

During the 1971-72 anchovy reduction season, two more anomalous
ancliovy otoliths were collected. On January 13, 1972, an otolitli narrow
on the dorso-A'entral axis (Figure IB) was collected from a female
anchovy caught in tlie San Pedro Channel. A typical otolith with one
annual ring measures 3.8 mm (0.15 inch) long and 1.7 mm (0.07 inch)
wide. Tlie length of this one-ring otolith is normal, but its widtli is only
1.3 mm (0.05 inch) or three-fourths tlie widtli of an average otolith.
Otoliths of tliis type are rare, only a few hav(> been observed in the
22,000 otoliths examined.

On January 17, 1972, an oval shaped otolitli (Figure IC) Avas col-
lected from another female anchovy caught in the San Pedro Channel.
This one-ring otolith measured 1.7 mm (0.07 inch) wide and 3.0 mm
(0.12 inch) long. The width is normal, but the length is much shorter
than average. To my knowledge this is the only anchovy otolith with
these characteristics that has been reported.

The age, length, Aveight and sex of the three anchovies from which
the otoliths w-ere taken are similar (Table 1).

TABLE 1
Age, Length, Weight, and Sex of Anchovies From Which Otoliths Were Taken

Anchovy witli
typical otolith

Anchovy with
narrow otolith

Anchovy with
oval otolith

Age

128

21.0

female

120

17.3

female

Length (mm 9i.)

Weight (g)

129
21.1

Sex

female

The different shaped otoliths probably reflect a genetic trait because
of their limited occurrence. Completely calcified otoliths and transpar-
ent otoliths occur much more frequently and could reflect an environ-
mental factor which affects the formation of calcified body parts.

REFERENCES

Collins, Robson A. and Jerome D. Sprat t. lOGD. Arc determination of the north-
ern anchovy from otoliths, p. 39-55. In The northern anohovv (Engraulis mordax)
and its fishery, 1065-GS. Calif. Dept. Fi.sh and Game, Fish liull., (1-17): 1-102.

— Jerome D. Spratt, Operations Eesearch Branch, California Depart-
ment of Fish and Game. Accepted March 1975.

NOTES

237

THE STEWART MODIFIED CORRAL TRAP

In conjunction with the North Kings Deer Management Project
(Bertram 1973), deer Avere trapped for marking and radio collaring to
establish migration routes, delay areas, and to aid studies on fawn
production and survival. Winter range deer trapping provided inform-
ation on deer movement to various sections of the summer range ; how-
ever, some gaps occurred regarding movements to and from certain
sections of the summer range. In order to fill in these gaps it was
decided to trap deer on the summer range at selected locations.
Attempts with snares (Ashcraft and Reese 1957) and baited Clover
traps (Clover 1956) in the summer of 1971 were unsuccessful.

In the summer of 1972, trapping on the summer range was attempted
using a corral trap consisting of five 2.1 m x 2.1 m (7 ft x 7 ft) panels
and a slightly modified gate from an "Oregon Panel" trap (Anon.,
1962). Three does were subsequently caught. One escaped during han-
dling, one killed itself when it hit the gate attempting to escape and the
third broke the gate and escaped.

Bin Stewart, Department of Fish and Game Fresno Unit Wildlife
Manager, suggested attaching a Clover Trap to the corral trap to alle-
viate injury and handling problems. The idea was that a deer after

FIGURE 1. A Stewart Modified Corral Trap in place. The main gate, front, is a large
version of a Clover trap gate. One of the Clover traps is visible at the left
rear. Photo by R. Bertram.

238 CALIFORNIA FIPTI AND GAME

getting trapped in tlie corral Avould enter tlie Clover trap Avhile trying
to escape and be held there, minimizing the chances of the deer injur-
ing themselves. In the summers of 1!)73 and 1074 the Stewart Modified
Corral Traj) was field tested.

METHODS AND MATERIALS

The basic corral trap consists of 7 panels, each 2.4 m x 2.4 m (8 ft
X 8 ft) constructed of 2.5 cm x 15.2 cm (1 inch x 6 inch) boards (13
per panel). Tlie panels are then arranged in an octagonal shape (Fig-
ure 1). Heavy wire is used top and bottom to attach adjacent panels
together at the corners. The eighth side is comprised of the main gate.
Holes are cut into two of the panels to accommodate the gate ends of
the Clover trap. The Clover traps are inserted into these holes so that
the gate end is flush with the inside of the panel. The Clover traps are
held in place by anchoring the middle of each side and the rear to
rocks buried in the ground and by wiring (heavy wire) each side of the
inserted end of the Clover trap to tlie corral panel.

The main gate mechanism is essentially a larger scale of tliat used
on a Clover trap. The trigger mechanism for the corral trap is also
essentially the same as used on the Clover trap except that horizontal
trip strings Avere utilized.

RESULTS AND DISCUSSION

Nine deer (plus a recapture) were trapped and marked at one trap
site. It is of interest that all deer entered and were trapped in the
Clover traps while attempting to escape. In fact the first deer entered
the Clover trap and was cauglit even though the main corral gate failed
to drop because of improper setting.

The deer trap was constructed to encircle a cattle salting area that
has historically sliown heavy deer use. Deer visited the salt lick nor-
mally at niglit although several were observed around it during the
day. The period when deer seem to seek out salt most at this elevation
1,829 m (6,000 ft) is during June and July.

Cattle became a problem, getting caught in, and breaking boards on
the corral, so a three-strand barbed wire fence was i)ut in a half circle
in front of the main gate. The fence was dropped when the trap was
not in operation. Also, the main gate was securely tied up so both
cattle and deer could use the salt lick.

The Stewart Modified Corral Trap has numerous advantages over
other types of traps.

1) Deer are not as prone to injury when held in a Clover trap;
injuries are relatively common when using a corral trap.

2) The described trap can be placed around an established salt lick
or water and no additional bait is needed.

3) The trap can be set in the evening and checked in the morning
whereas snares must be closely monitored.

4) The gate can be tied up for any period of time allowing free
movement to and from the salt lick for both cattle and deer.

NOTES 239

ACKNOWLEDGEMENTS

Bill Stewart of The Department of Fish and Game should be cred-
ited "with the idea for the trapping apparatus and Hal Sahvasser, Uni-
versity of California, Berkeley, helped with early stages of develop-
ment and trapping operations.

REFERENCES

Anonymous. 19G2. Panel deer trap. Oregon State Game Commission memo. 2 p.

Ashcraft, Gordon, and Don Reese. 1957. An improved device for capturing deer.
Calif. Fi.sh Game, 43(3) : 19^199.

Bertram, Ronald C. 1973. Complete deer management. Outdoor Calif., 34(G) : 3-G.

Clover, Melvin R. 195G. Single gate deer trap. Calif. Fish Game. 42 (3): 199-
201.

— Eonald D. Bcmpcl and Ronald C. Bertram, Wildlife Management
Branch, California Department of Fish and Game. Accepted Novem-
ber 1974.

THE STATUS OF ROCKY MOUNTAIN
ELK IN KERN COUNTY, 1974

HISTORY

On December 6, 1966, Department of Fish and Game issued a permit
to Mr. Eex C. Ellsworth for the importation of 300 Rocky Mountain
elk (Cervus c. canaelcnsis) from Yellowstone National Park to be re-
leased into a fenced compound on his ranch in southern Kern County,
California (Figure 1). The Ellsworth Ranch is on Cummings Mountain,
approximately 16 km (10 miles) southwest of the town of Tehachapi.

By April 24, 1967, 290 elk had been shipped from Yellowstone, but
due to the stress of transport and possibly other causes, only 277 sur-
vived to be released inside the ranch enclosure.

Many elk died within the enclosure. In mid-1967 wildlife pathologist
Oscar Brunetti (California Department of Fish and Game) reported
that animals were dying from several disease entities brought
on by stress induced by confinement and a new^ and different diet. At
that time, losses had just about ended. Elk began escaping by about
the middle of 1967 because of lack of fence maintenance. In early
1968 Department of Fish and Game personnel reported that approxi-
mately 15 elk were outside the enclosure and were scattered on Tejon
Ranch lands to the south and west and on Cummings Valley and Bear
Mountain to the north. Another 1968 report indicates that 24 animals
re-entered the enclosure and were trapped. Eight animals were outside
and near the enclosure at that time. This same report estimated 12
animals on Tejon Ranch and 12 on Cummings Ranch. It is not known
exactly how many animals escaped to the wild.

240

CALIFORNIA FISH AND GAME

%''

■\

y,*-''- B M

FIGURE 1. Rocky Mountain elk in the Ellsworth Ranch enclosure. Photo taken by W. Mac-
gregor, 1967.

PRESENT STATUS

Field surveys aiid interviews "were conducted durinp: Aiignst and
September, 1974, to update data on the Tehacliapi elk herd. Fresh and
recent elk sign were found in several areas; the Peckerwood Basin-
Cottonwood Creek area of the Tejon Ranch (especially Sections 8, 9,
and 10, T 10 N, R 16 W S.B.B.M.) contained sign of at least three
bands of eight to fourteen animals each. The Lopez Flats area and sur-
rounding ridges on the Tejon Eanch showed sign of 10 to 20 animals.
Two areas (Section 13, T 10 N, R 17 W, and Sections 19, 20 and 30,
T 10 N, R 16 AV), contain the most sign and probably provide habitat
for two separate populations, thougli some movement and inter-mingling
probabl}- occurs. Both of these areas have grassy slopes and willow-lined
drainages witli abundant water. Elk browse on willows and wallow in
mudholes in the creeks during the summer months.

Current information indicates these two areas are probably the most
densely populated with elk. Field surveys revealed that small numbers
of elk are scattered over wdde areas of the Tehachapi Mountains and
probably wander over large areas of range.

Tejon Canyon and the Brush Spring Tributary provide suitable elk
habitat, although heavy livestock use in the area probably masks elk
sign.

Some areas of Cummings Mountain and nearby Cedar Creek have
habitat suitable for elk, for at least a portion of the year.

NOTES

241

The southeast-facing slope of the Tehachapi Range, facing Antelope
Valley, is indented with numerous drainages, most with abundant water,
and many with grassy, willow-lined stream courses suitable for elk.

Several areas on the north end of the Tehachapis show elk usage. An
estimated four to eight elk are regularly inhabiting the area near Syca-
more Canyon. Other reports suggest widespread usage by elk in and
around Bear and Cummings Valleys. Bear Mountain has islands of
suitable elk habitat and bulls, cows, and calves have been reported
there. Intensive development of Bear Mountain is drastically reducing
wildlife values there, however.

Large areas in and near Horse Thief Flat and Oak Flat may sup-
port elk, especially when acorns provide ample feed there.

Elk have been reported at very low elevations in Tejon Canyon and
at the mouth of El Paso Creek.

Nearly 100 elk may now be living in the Tehachapi Mountains,
Table 1.

TABLE 1. Estimates of Elk Numbers by Area

Area

Peckerwood Basin-Cottonwood Creek

Lopez Flats

Tejon Canyon

Cummings Mountain-Cedar Canyon.

Sycamore Canyon-Bear Valley

Bear Mountain

Totals

Estimate of
minimum number

Estimate of
maximum number

DISCUSSION

Since evidence of reproduction has been noted in each of the past 4
years, it is apparent that the elk have adapted to their new range. Dis-
tinct bands are occupying islands of suitable habitat and are moving
seasonally from one area of suitable feed to others. In addition, small
bands or individuals seem to wander over wide areas of range.

Riparian habitat is preferred during summer months when succulent
grasses, forbs, and willows provide the bulk of the animals' diet. Dur-
ing the fall, elk disperse to oak groves and higher slopes to feed on
acorns and browse. After winter rains begin, and into the spring
months, grasses are abundant over most of the Tehachapi range.

It seems likely that elk numbers are reaching a balance with the
average carrying capacity of these islands of suitable habitat. Pres-
sures of livestock grazing will influence this carrying capacity. In
addition, deer numbers are increasing dramatically on some portions
of the Tejon Ranch and are presenting a negative impact on elk, deer,
and livestock habitat and on the range in general.

No damage by elk has been reported, and all landowners and other
persons interviewed expressed desire to preserve the herd.
— Ronald D. Thomas, Wildlife Management Branch, California Depart-
ment of Fish and Game. Accepted for publication November 1974.

242

CALIFORNIA FISH AND GAME

MODIFICATION OF THE CLOVER DEER TRAP

The Clover (1954, 195G) deer trap, consisting of a metal pipe frame
covered by heavy nylon mesh, has many advantages related to its light
weight and ease of movement. It has the disadvantage that a trapped
animal can see the approaching trap crew, and usually hurls itself
excitedly about inside the trap. Injuries are likely if the animal is not
restrained quickly.

In my experience with the white-tailed deer (Odocoilcus virginianus)
on the George Reserve in Michigan the catch-net design of Clover
(1954) is quite inefficient. It takes time to set correctly, and despite my
best efforts, a fair number of animals elude the net. Redesign of the
catch-net to use both ends of the purse string to close the purse instead
of just one, which closes the purse in half the time, resulted in im-
proved efficiency of capture. Still, a number of animals escaped.

Use of the catch-net also involves liazards to the trapping crew.
Safely handling our large deer — large males weigh well over 90 kg
(200 pounds) — involves a crew of at least three men.

FIGURE 1. Diagram of the collapsible deer trop, showing general construction and set-up
of the trap. The inset shows detailed construction of the corners. Both pipe
frame end pieces are constructed identically for complete interchangeability;
however, drop bar guides are bolted only to the drop gate end.

NOTES 243

The Clover trap construction details were modified to allow rapid
collapse of the trap to restrain tlie animal (Figure 1). This collapsing
design is less cumbersome than that of Sparrowe and Springer (1970)
and allows rapid collapse and re-resetting. Furthermore, tlie trap can
be collapsed for transport without unlacing netting as is required in
the Clover (1954) design.

The collapsible design showni in Figure 1 could be applied to any
pipe-frame, net covered trap. I am including the specific design details
of the traps used on the George Keserve since many problems of econ-
omy, ease of construction, and maintenance have been solved, and the
same trap would be useful on any deer-sized animal.

Dimension of the pipe frame in the traps are 106.7 cm (42 inches)
for all of the end pieces and 167.6 cm (66 inches) for the long sides.
The sides and drop-gate guides, 1.27 cm (^ inch) black pipe, are bolted
onto the rigidly welded end-frame, 1.9 cm (J inch) pipe, members. The
sides of the end frame are welded solidly to the tops and bottoms, 7.6
cm (3 inches) in from their ends. The drop-gate guides are bolted flush
with the end of the top and bottom end frame pieces. The drop-gate
is 3.2 cm (1^ inch) black pipe, 95.3 cm (37.5 inches) long, with 7.6
cm (3 inch) diameter rings welded to each end.

The mesh covering the trap is knotless netting of No. 84 nylon twine
145.2 kg (230^ pounds) test, with 10.2 cm (4 inch) square mesh
(available from Nichols Net and Twine, East St. Louis, Illinois) treated
with net set. Side pieces of mesh must be put on in a square pattern
for the trap to collapse. With the trap made with dimensions given
above, each side consists of a piece 10 squares by 15 squares. Tops and bot-
toms of the side piece can be looped over the unbolted side pipes, but the
ends must be lashed with nylon rope. The top and closed end should be in
a single piece using the diamond pattern and measuring 17 diamonds
long by 7 diamonds wide, lashed on with nylon rope. The drop-gate
should be a separate piece because it wears out most quickly and should
be easily replaced. Furthermore, if it is made continuous with the top
and closed end, the hitting of the closed end by the trapped animal
tends to slide the netting in that direction with a consequent lifting
of the drop-gate and possible escape. The drop-gate is cut in diamond
patterns (7 diamonds high by 8 diamonds Avide), looped over the drop
bar and unbolted drop bar guides and lashed at the top. No netting
is required on the bottom of the trap. The trigger mechanism is a rat
trap similar to that described by Clover (1956).

In the field, the trap is held in place by deadmen or heavy stakes at
each bottom corner, and guylines from each top corner leading at a
45°-50° angle downward to secure stakes. The guylines at the rear
are fastened permanently, but the two at the front are attached by
quick detachable snaps.

When an animal is captured, the two guylines at the front are un-
snapped, and the trap collapsed on the animal. The animal can be
restrained by a single handler by tying the collapsed top side pipe to
the bottom side pipe.

The animal can be released easily by tying the drop-gate open, going
to the rear of the trap, and lifting the trap to its upright position. The
deer can pass out the open door away from the handler.

244 CALIFORNIA FISH AND GAME

With this trap a sinprle worker oan handle antlered, rutting bucks
weighing- over 200 pounds with ease and safety. Tlie traps have proven
to be sturdy, flexible, and easy to maintain.

LITERATURE CITED

Clover, M. R. 1954. A portable deer trap and catch-net. Calif. Fish Game, 40(4) :
367-373.

. 195G. Single-gate deer trap. Calif. Fish Game, 42(2) : 199-201.

Sparrowe, R. D. and P. D. Springer. 1970. Seasonal activity patterns of white-
tailed deer in eastern South Dakota. J. Wildl. Manage., 34(2) : 420-431.

— Dale R. McCullough, School of Natural Resources, Univ. of Michigan,
Ann Arhor 48104. Accepted for publication December 1974. Sup-
ported bxj NSF Grant GB-6171.

NOTES

245

BLOOD AND SERUM ANALYSES OF ADULT STRIPED

BASS, MORONE SAXATIUS, CAPTURED IN

THE SACRAMENTO RIVER

Fisheries liematological literature has been primarily concerned with
the establishment of blood parameters for salmon ids. The lack of basic
hematological data for other species presents problems when attempt-
ing to assess their physiological state. Additional problems of inter-
pretation arise from the diverse and varied techniques and reporting
formats used. Blaxhall (1972) suggested several standard techniques
Avhich were previously applied only to higher vertebrates. This would
provide for better repeatibility, and allow for a comparison of results
among fish groups. The purpose of this project was to provide basic
blood and serum data for Morone saxatilus (Walbaum) using estab-
lished techniques.

During early fall of 1972, several migrating striped bass, M. saxa-
tilis, were captured in fyke traps on the Sacramento River near Free-
port, California. Lengths were recorded for each fish, a blood sample
(3.0 ml) was obtained via heart puncture and the fish returned to the
river.

The blood samples were immediately mixed with heparin and iced
until analyses could be performed. The samples were analyzed for
hematocrit and hemoglobin content ^ using standard techniques (Blax-
hall 1972). The remainder of the blood was centrifuged, the serum
pipetted and frozen until processed on an SMA micro 12 serum
analyzer.

The results of all analyses are presented in Table 1. This is the first
report of blood parameters for this species captured from a freshwater
environment.

TABLE 1. Results of Adult Striped Bass Blood and Serum Parameters Collected
on September 19, 1972, Water Temperature 19''C.

Length (cm)

net (%)

Ub (gm/100 ml)

Na^- (meq/L)

K+ (meq/L)

Cholesterol (mg %)

Ca++(mg%)

Inorganic Phosphate (mg % P).

Glucose (mg %)

BUN (mg%)

Uric Acid (mg %)

Total Protein T.P. (gm %)

Alkaline Phosphate (mU./ml) .
SGOT/340 (mU./ml)

Fish number

103

8.0

10.3

9.0

7.0

125

ICO

100

120

1.57

5.10

3.73

3.35

3.70

285

410

345

305

480

9.5

13.5

10.0

11.0

10.9

9.5

10.0

0.7

0.9

5.9

440

105

115

525

123

0.0

2.3

3.0

5.0

2.0

5.45

1.00

0.30

4.10

0.15

4.2

5.8

4.7

4.3

5.1

580

137

2.05

108
51
12.
100
2.
350
15.0
10.0
105
2.5
0.40
5.3
13
43

1 The Unopette Sy.stem (Becton-Dickinson, No. 5857) was used for hemoKlobin
analyses. This is a modiflcation of the Standard Cyanomcthmoglobin procedure
(Cannan, 1958).

246 CALIFORNIA FISH AND GAME

ACKNOWLEDGEMENTS

This paper is i)art of a doctoral dissertation i'or the University of
California, Davis. This research "was supported by the National Insti-
tutes of noalth (Traininjr Grant Number ES 125-5) administered
throu<j:h the Deivirtmcnt of Envii-oinnentnl Toxicolojry. University of
California, Davis, California. John Kowell and William Shoales of the
California Department of Fish and Game and their seasonal aides are
greatly appreciated for their assistance in collection of striped bass.

REFERENCES

Blaxhall, 1'. C. 1072. The hematological assessment of tlie health of freshwater
fish. A review of selected literature. J. Fish. Biol., 4 : 503-004.

Cannan, R. K. 1058. Proposal for a certified standard for use in hemoglobino-
metry. Second and final report. Clin. Cheni., 4(3) : 240-251.

— Louis A. Courtois, Environmental Services Branch, Water Pollution
Control Lahoratory, RancJio Cordova, California 95670. Accepted
March 1975

NOTES 247

MEASURING SALMON, AN OLD AND
UNFAMILIAR METHOD

AVhile Avorking with salmon data collected off northern California
from 1948 into the early 1950 's I had occasion to compare some weights
and lengths with similar data from 1919 and 1920 pnblished in Cali-
fornia Department of Fish and Game Fish Bulletin No. 34, "The
Salmon of the Klamath River", by John 0. Snyder. The differences led
me to the inescapable conclusion that Snyder's fish and mine had not
been measured the same way. How had Snyder's been measured? The
old fisheries pioneer had died, and his bulletin gave no hint that I
could find.

Ever since the Department of Fish and Game re-started its sampling
of the commercial salmon catch in the 1940 's the measurement used for
scientific studies has been the caudal fork length, though frequently the
total length was also taken. Snyder had used a measurement that
appeared to be greater than the fork length, less than the total. This,
of course, ruled out standard length which is less than fork.

After stewing over the problem I relegated it to the back of my mind
where it remained for some time. Then a visitor dropped by my office.
It was W. L. Scofield, then retired, since deceased. Scofield had had a
long career with the Division of Fish and Game. After we had chatted
awhile I had a thought and asked him if he knew how Snyder's salmon
measurements had been taken. He was highly amused and said he was
only too familiar with it, having measured several thousand salmon for
Snyder. He went on to explain that the salmon were usually spread out
on a cannery or fish house floor and to measure them Snyder placed the
end of a flexible steel tape against the tip of the snout and passed the
tape over the curve of the body to the tip of the central caudal rays.
Because of the curve of the body this gave a measurement somewhat
longer than the fork length as used today, but less than the total length.
Scofield went on to say that the method did have the advantage of
speed because the fish could be measured without moving them, but
that he had argued against its use and had been over-ruled.

The presently used measurement can be obtained by sliding the fish
onto a measuring board which has a ruler set into the bottom and a
perpendicular stop at one end. The salmon's snout is held against the
perpendicular end and the measurement is to the central rays of the
caudal fin.

Snyder makes no mention of whether his fish were weighed dressed
or round. I believe anyone wishing to use Snyder's data would be safe in
assuming that all w^ere measured round. Gill net catches landed in
California were round until the fisheries were abolished by law. Ocean-
caught salmon taken soutli of Eureka were still being landed round
in the 1950 's.

— Donald H. Fry, Jr., Anadromous Fisheries Branch, California De-
partment of Fish and Game (Retired). Accepted November 1974.

248 CALIFORNIA PISH AND GAME

FURTHER RECORD OF LITTLE KERN GOLDEN TROUT,

SALMO AGUABONITA WHITER IN THE LITTLE

KERN RIVER BASIN, CALIFORNIA

In a recent study of phenetic variation among six populations of
f^olden trout, Salmo arjuahonita Jordan, collected in 1973 from the
Sierra Nevada, California, wc reported the presence of at least two
significantly distinct phenetic groups of golden-like trout resident
within the upper Little Kern Kivcr basin (Gold and Gall lOToa). The
first was represented by two samples, one from the Little Kern River
near Peck's Canyon Creek, and the other from lower Soda Springs
Creek near its confluence Avith the Little Kern River. Subsefpiently,
Gold (1975) reported that this group occupied a cluster point in
phenetic hyperspace approximately halfway between that occupied by
rainbow trout (Salmo gairdncri Richardson) and that by S. aguahonita
oguahonita — the golden trout subspecies from the South Fork of the
Kern River and Golden Trout Creek.

The second phenetic group was represented by a single sample from
upper Soda Springs Creek, above a series of natural barriers which
prevent the upstream migration of trout from lower Soda Springs
Creek and the Little Kern River. Phenetically, this group was found
to be much more closely related to the geographicall}' distant popula-
tions of S. a. agndboniia than to the samples from lower Soda Springs
Creek and Little Kern River situated only 10-11 km (6-7 miles) down-
stream (Gold and Gall 1975a). This evidence, plus some differences
in chromosome karyotype (Gold and Gall 1975?j), and a remarkable
similarity in morphology between the upper Soda Springs Creek trout
and Evermann's (1905) first description of the Little Kern golden
trout, led us to hypothesize that the upper Soda Springs Creek trout
re])resented a "])ure" ])opulation of the endemic, and now threatened
(Miller 1972; Fisk 1972), Little Kern golden trout, 8. a. whitci Ever-
mann.

Subsequently, a search -was undertaken for additional populations
that might represent "pure" Little Kern golden trout. In June 1974,
20 specimens w'ere removed by angling from Deadman Creek, a north-
ern tributary of Soda Springs Creek, and tested for phenetic similarity
Avith the upper Soda Springs Creek population. Trout were caught at
random sites along the creek, but always upstream from a series of nat-
ural barriers which prevent any upward migration of trout from below^

Ten meristic characters were examined on all specimens in the same
manner as described in Gold and Gall (1975a). All data were subjected
initially to frequency distribution analysis using the mean, variance,
and Fislier's third and fourth moment statistics (Sokal and Rohlf
1969). Evaluation of the distributions revealed that all ten characters
w^ere distributed approximately normall.y. Slight deviations from nor-
mality were invariably leptokurtotic and were considered as being due
to small sample size.

The means of the ten characters for both populations were compared
by "t" tests, with each test having 111 degress of freedom.

NOTES

249

Means of 8 of tlie 10 characters were found not to differ significantly
at the 5% probability level (Table 1). Of the two means which differed
significantly between the two samples, one (scales above the lateral
line) differed at the 5% probability level but not at the 2% level. The
reduced number of vertebrae in the Deadman Creek trout was highl}'-
significant (P < 0.01), and was the only clear cut difference between
the two samples.

TABLE 1

Observed Means and Standard Errors of 10 Characters for 20 Deadman Creek and

93 Upper Soda Springs Creek Trout, and the Results of "t"

Test Comparisons Between Means

Character

Pyloric caeca

Fin rays

Pelvic

Dorsal

Anal

Pectoral

Branchiostegal rays

No. vertebrae

Gill rakers

Scales along lateral line.
Scales above lateral line

Mean ± S.E.

Deadman
Creek

30. C ± 0.4

9.0
12.2
11.5
15.4
11.1
59.9
17.8
181.0
35.2

0.1
0.1
0.1
0.1
0.1
0.1

± 0.2

1.2
0.3

Upper Sodat
Springs Creek

32.2 ± 0.4

9.5
11.9
11.5
15.5
11.3
CO. 8
18.2
181.8
30. 0

0.1
0.1
0.1
0.1
0.1
0.1
± 0.1
± 0.9
± 0.3

Pooled t
standard

0.884

0.197
0.241
0.230
0.192
0.202
0.209
0.326
2.112
0.C84

"t"

1.753

0.701

1.245

0.217

0.260

0.990

4.067**

1.227

0.379

2.050*

t From Gold and Gall (1975a).

t The pooled standard error for the "t" tests was computed after Sokal and Rohlf (19G9) using a

weighted analysis for unequal sample size.
* P < 0.05.
** P < 0.01.

The high degree of similarity (8 of 10 means) strongly indicates
taxonomic identity between the two populations. The differences be-
tween them may be the result of environmental variation. This could be
true for the different vertebral numbers observed, since relatively slight
alterations in environmental variables (specifically temperature) are
known to modify this character in salmonids (Taning 1952; Garside
1966). Also, slight population divergence by chance alone might be ex-
pected since these two populations may have been isolated from each
other for some time.

Since both the Deadman Creek and upper Soda Springs Creek popu-
lations are sufficiently isolated from each other, and from the trout
populations of lower Soda Springs Creek and the Little Kern Eiver,
the two populations, although isolated, very probably represent a single
form of golden trout long resident in the upper Little Kern basin. This
would appear to support our earlier finding that relatively "pure"
populations of Little Kern golden trout still reside in Avaters of the
Little Kern Eiver basin. Furthermore, the finding of a second popula-
tion, closely related phenetically to the upper Soda Springs Creek
population and hence by inference distantly related to the lower Soda
Springs and Little Kern River populations, reinforces our earlier con-
tention that the trout of lower Soda Springs Creek and the Little Kern

250 CALIFORNIA FISH AND GAME

River arc not tlie cndemie golden trout of the region, but rather rem-
nants of golden X rainbow hybridization (as suggested by Dill 1945,
1950). This contention was supported by the fact that the lower Soda
Springs Creek and Little Kern River trout were phenetically inter-
mediate between S. (jairdncri and <*^'. a. ofjuahonita (Gold 1975), and
by tlie close phenetic relationship observed between S. a. aguahonita
and the upper Soda Springs Creek golden trout ("Cold and Gall 1975rt).

REFERENCES

Dill, W. A. 1945. The Little Kern River Drainage. Tulare County. Progress Re-
port No. 2. Calif. Dopt. Fish and CJanio. Inland Fish. Admin. Rep., 4.V20. 10 p.
(mimeo.)

Dill, "W. A. IO.jO. a report on the golden trout fishery of California. Calif. Dept.
Fish and Game, Inland Fi.sh. Admin. Rep., ."O— }4. 28 p. (mimeo.)

Evermann, li. AV. IIK).". The golden trout of the southern High Sierras. U.S. Bur.
Fish. Bull., 2.") : l-ol.

Fisk, L. 1972. Status of certain depleted inland fishes. Calif. Dept. Fish and
Game, Inland Fish. Admin. Rep., 72-1. 13 p. (mimeo.)

Garside. E. T. 19G(5. Develoiiniental rate and vtM-tohral nmnbor of salinmiids. .1.
Fish Res. Bd. Canada, 23: 1537-15.".!.

Gold, J. R. 1975. Phenetics and genetics of High Sierran golden trout. Cal-
Neva Wildlife. In press.

Gold, J. R.. and G. A. E. Gall. 1975rt. The taxononiic structure of six popula-
tions of golden trout (Salmo aguahonita) from the Sierra Nevada, California.
Calif. Acad. Sci.. Proc.. 40(10) : 243 2G3.

Gold, J. R., and G. A. E. Gall. 1975''. Chromosome cytology and polymorphism
in the California High Sierra golden trout (Salmo ngiinhoiuta) . Can. J. Genet. &
Cytol.. 17: 41-53.

Miller, R. R. 1972. Threatened freshwater fi.shes of the United States. Amer.
Fish. Soc, Trans., 101(2) : 230-252.

Sokal, R. R., and F. J. Rohlf. 19C9. Biomeiry. AV. II. Freeman and Co., San
Francisco and London. 776 p.

Taning, A. \. 1952. Experimental study of meristic characters in fishes. Bio.
Reviews, 27 : 169-193.

ACKNOWLEDGMENTS

The autliors express tlieir gratitude to D. P. Christenson of the Cali-
fornia Department of Fish and Game for his assistance in procuring
the Deadman Creek specimens. We also thank S. J. Nicola for reading
the manuscript and offering helpful suggestions.

— J. R. Gold and G. A. E. Gall, Department of Animal Science, Univer-
sity of California, Davis, California 95616. Accepteel March 1975.

NOTES 251

POECIUOPSIS GRACILIS (MECKEL), A NEWLY
INTRODUCED POECILIID FISH IN CALIFORNIA

Oil 27 July 1974, four specimens of a poeeiliid previously unreported
in California were collected with a minnow seine in an irrigation canal
at the junction of U.S. Highway 111 and Johnson Avenue, near Mecca,
Riverside Countj^, California. The specimens were identified by Dr.
Carl L. Hubbs (Seripps Institution of Oceanography) as Pocciliopsis
gracilis (Heckel), 1848 (Rosen and Bailey 1966).

Pocciliopsis gracilis is native to freshwater streams on both the Pa-
cific and Atlantic slopes of southern Mexico and Guatemala (Rosen
and Bailey 1966). Males reach 30 mm tl and females 50 mm (1.17 and
1.95 inches, respectively). Their preferred water temperature is 22-24 C
(71.6-75.2 F) (Sterba 1962). Observations in the field and in aquaria
suggest that P. gracilis prefers moderately fast-moving water and is
active throughout the Avater column.

P. gracilis resembles the mosquitofish, {Gamhiisia affinis), but is read-
ily distinguished in the field by a longitudinal row of four to eight
large, jet-black spots; the males have an extremely long anal fin (gono-
podium), extending almost to the caudal fin when depressed. Rosen and
Bailey (1966) have reviewed the nomenclature of this species of which
Hctcrandia plcurospilus (Jordan and Evermann 1896) and Poccilistes
pleurospihis (Sterba 1962) are among the synonyms. The common name
"porthole live bearer" is suggested, as a modification of "porthole
fish" used by Sterba (1962).

P. gracilis should not be confused with the Gila topminnow, P. occi-
deiitalis, which was formerly abundant in the Gila River system of
Arizona (Minckley and Deacon 1968; Minckley 1973; Carl L. Hubbs,
pers. comiii.). The specimens I collected, one immature male (21 mm
SL) (0.82 inch) and three half-grown females (14-20 mm) (0.55-0.78
inch) were readily distinguished from other resident stream poeciliids
by the four to five very distinct, jet-black spots on each side of their
translucent tan body.

Twelve additional specimens, ranging in size from 8 mm (0.31 inch)
juveniles to a 43 mm (1.69 inches) female, were collected on 17 No-
vember 1974 at the same site (Table 1). At least a dozen more were
observed schooling with young of shortfin molly, P. mcxicana and red
shiners, Notropis luircnsis. The appearance of recently born young,
the wide range of sizes, and the persistence of the fish for at least a
4-month period, suggest that P. gracilis is a reproducing resident of
this canal.

The species was not represented in collections I have previously made
at this site, nor have I obtained P. gracilis in samples from other nearby
Coachella Valley canals and waterways sampled periodically since
1964 (i.e., canals at Avenues 81, 82, and 83 near Highway 86 as de-
scribed by St. Amant and Sharp (1971) and the Whitewater River,
Riverside County). Thus, the introduction appears to be recent, pos-
sibly early in 1974. Possible sources of introduction were not investi-
gated but presumably were by direct release by aquarists or escape-
ments from a nearby tropical fish farm.

252

CALIFORNIA FISH AND GAME

Eiprlit additional species, representing a total of four families, were
recorded from tlio Jolmson Avonno canal in 1974 (Tabic 1). The as-
scmbla<^c was dominated by sailfin mollies {Poccilia latipinna) and
shortfin mollies and by red shiners. Pocciliopsis gracilis, mosqnitofish,
and desert ])npfish {Cifprinodon macuJarius) were common but not
abundant. One small "jjreen waj;"" variety of the ^rccn swordtail.
Xiphuplionis JkIIcH, was also collected on 27 July 1974 (juvenile, 22
mm) (0.87 inch). It is also known to have been released in a drainage
canal at Avenue 82 near Highway 86 in tlie Coachella Valley ; although
this stock did not survive (St. Amant, Calif. Dept. Fish juid Game,
pers. comm.) it may have been the source of this specimen. However,
tlie variated platy, Xiphophorus variatus, also previously' described
from the Avenue 82 site (St. Amant and Sharp 1971), was not found
here.

TABLE 1

Fishes Collected and Observed in an Irrigation Canal at U.S. Highway 111 and
Johnson Avenue, 1 mile south of Mecca, Riverside County, California

Species

Cyprinidae

Cyprinus carpio

Notropis lutrensis

Cyprinodontidae

Cyprinodon macularius

Poeciliidae

Gambusia affinis

Poecilia latipinna

P. mexicana

Poeciliopsis gracilis

Xiphophorus helleri

Cichlidae

Tilapia sp

Total species

Time of day

Air temperature, C

Water temperature, C

pH....

Number collected (+ = observed only)

20 January
1974

1
c

Midday
21
20
7.8

27 July
1974

130

Late afternoon

17 November
1974

+
22

1.")

MorninK

7.8

Total

25 +

32 +

17+

208+

99 +

1 +
9

Finally, carp {Cyprinus carpio), ranging in size from 7 to 28 cm
(2.8 to 11.0 inches) and a number of tilapia {Tilapia sp.) were ob-
served and captured in deeper portions of the canal. The identification
of the species of Tilapia has not been confirmed, but it does not appear
to be T. mossamhica (as previously reported from Imperial County by
Hoover and St. Amant 1970) .

NOTES 253

p. gracilis does not now threaten sport fish populations, but it does
represent one of many recent introductions which may compete with
remaining native fishes sucli as the desert pupfisli. Studies on food
habits and behavior are warranted. Likewise, ecological studies of the
present irrigation canal assemblages are warranted since the canals
may serve as reservoirs for further invasions.

ACKNOWLEDGEMENTS

I thank Rick D. Cardwell, Dow Foreman, M. James Allen, James
A. St. Amant, and especially Carl L. Hubbs. Specimens from the 27
July 1974 collection are deposited in the fish collection of Scripps
Institution of Oceanography (51074-126).

REFERENCES

Hoover, F. G., and J. A. St. Amant. 1970. Establishment of Tilapia mossamhica
Peters in Bard Vallej', Imperial County, California. Calif. Fish and Game, 56(1) :
70-71.

Jordan, D. S., and B. W. Evermann. 1896. The fi.shes of North and Middle
America. U. S. Nat. Mus. Bull., 47. 3313 pp.

Minckley, W. L. 1973. Fishes of Arizona. Ariz. Game and Fish Dept. XV +
293 pp.

Minckley, W. L., and J. E. Deacon. 1968. Southwestern fishes and the "endan-
gered species". Science, 159: 1424-32.

Rosen, D. E., and R. M. Bailey. 1966. The poeciliid fishes (Cyprinodontiformes),
their structure, zoogeography and systematics. Bull. Amer. Mus. Nat. Hist.,
126(1) : 1-176.

St. Amant, J. A., and Ira Sharp. 1971. Addition of Xiphophorus variatiis (Meek)
to the California fish fauna. Calif. Fish and Game, 57(2) : 128.

Sterba, -G. Freshwater fishes of the world. 1962 Translation. A'ista Books,
Longacre Press Ltd., London. 878 pp.

— Alan J. Mcarns. Southern California Coastal Water Research Proj-
ect. 1500 East Imperial Highway, El Scgundo, California, D0245. Ac-
cepted February 1975.

POLYMORPHISM IN POPULATIONS OF SCELOPORUS

OCCIDENTAUS IN SANTA BARBARA

COUNTY, CALIFORNIA

There exists in the literature two taxonomic schools of thought with
respect to the subspeciation of the western fence lizard, Sceloporus
occidentalis. Stebbins (1966) has recognized four subspecies, with two
of these, S. o. occidentalis and S. o. hiseriatns, possibly occurring in
Santa Barbara County. Other authors (Bell 1954; Cochran and Goin
1970) have recognized a total of six subspecies, with three of these,
;S^. 0. hocourti, 8. o. hiseriatns, and 8. o. longipes also possibly occurring
in Santa Barbara County. A criterion used by both schools of thought
for subspecific differentiation has been the pattern of the blue gular
throat patch — whether or not there exists a single patch, a partially
divided patch, or two completely separate patches. Both schools agree
that the patch (or patches) may be absent in adult females and
juveniles of either sex.

25-t CAI.TFORXIA FISH AND GAME

Concurrent -witli a study of five natural j)opulations of S. occidcntalis
in Santa Barbara County, California, it ^vas observed that 39%
(N=r97) of the adult males taken fi-oni these five populations durln<r
1970 and 1971 were totally devoid of any throat pateli. The reniainin<j:
61% possessed the expected variations in i)atch patterns as noted
above. These populations were {geographically separated along an ap-
proximate north-south transect through the county between the Coleta
Valley on the south and the Cuyanui Valley on the north. No grada-
tion in patch patterns or patchlessness was observed. Unless one Avere
cognizant of the fact that males of this species have enlarged postanal
scales (Stebbins op. cit.; Davis 1967), the patchless forms miglit be
mistaken for females. Prior to this study it was found through dissec-
tion that all animals taken from the study areas, Avhich had eidarged
postanal scales, were in fact males. Of particular note is the fact that
the patchless form fits neither of the current taxonomic schemes nor the
possible hoconrti X longiprs intergrades suggested by Bell (op. cif.)

However, it is felt that these populations should not be considered as
a separate taxonomic unit but rather they should serve as an additional
example of the highly polymorphic nature of this wide ranging species.

REFERENCES

Bell, Edwin L. 1954. A preliminary report on the .subspecies of the western
fence lizard, Sceloporus occidentalis, and its relationship to the eastern fence
lizard, Sceloporu.'i unduhifu.'i. Ilerpetolofjica, 10: 31-3G.

Cochran, D. M., and C. J. Goin. 1970. The new field hook of reptiles and amphi-
bians. G. P. Putnam Sons, New York.

Davis, J. 1967. Growth and size of the western fence lizard {Sceloporus occidcnt-
alis). Copeia, 19G7 : 721-731.

Stebbins, R. C. 19G0. A field ^uide to western reptiles and amphiliians. Houghton
Mifflin Company, Boston.

— Robert L. White, II, Department of Biological Sciences, University of
California, Santa Barbara, California 93106. Current address Depart-
ment of Zoology, Oregon State University, Corvallis, Oregon 97331,
USA. Accepted November 1974.

BOOK REVIEWS

Freshwater Ecology

By T. T. Macon, John Wiley & Sons, Inc., New York, Second Edition, 1974; viii + 341 p.
illus.

Tlie material in the second edition of Frcshwafcr Ecologij varied only slightly
from that of the original hoolv which was published in lOO.S. The new edition was
revised slightly to omit obsolete information, and some recent material was added.

The author subscribes to the belief that the reason species are present in some
places and absent from others is because of the interaction of limiting factors. To
support his convictions, Dr. Macau presents material on physical iuid chemical
properties of water, communities, transport, Itehavior, interrelationships, i)hysical
factors, oxygen, salinity, calcium, other chemical factors, production and study
methods.

I could not relate very well to examples the author used to sell his ])oints because
most of the material described acpiatic insects .and other invertel)rates. The role of
fish in the aquatic habitat was seldom covered.

A failure of this book is the use of names of animals. The author took great pains
to be comprehensible to all in using generic and specific names. In fact a list of
alternative names followed each chapter ; however, common or vernacular names
would often be more descriptive and less disruptive to a reader who isn't well versed
in the scientific names of invertebrates. — Larry K. Piickctt.

The Carnivores

By R. F. Ewer; Cornell University Press, Ithaca, New York, 1973. xv + 494 p., illustrated.
$21.50.

This volume, the product of the author's lifelong interest in and study of carni-
vores, is a pleasure to read. It is well written and presents an excellent review of
many aspects of the biology of the Carnivora. Not only does this work deserve a
place in the professional biologist's library, it also will be of interest to l;iymen and
amateur naturalists interested in carnivore biology.

The text begins with a succinct introduction to the Carnivora. including a brief
taxonomy and some characteristics and habits of each family. Chapter 2, "The
Skeleton", is a somewhat detailed analysis of the skeletal anatomy of the seven
families, including discussions of the post-cranial skeleton, the skull, aiul the denti-
tion. Of particular interest are the summaries of dental formulae and eruption
sequences.

Chapter 3, "Anatomy of the Soft Parts", is presented in somewhat less detail
than is skeletal anatomy. Included are discussions of the pelage, skin glands, rhina-
rium, ears, paws, and a very cursory treatment of the viscera. Chapter 4. "The
Special Senses", concerns vision, hearing, smell, taste, tactile senses, and their
relationships to carnivore biology.

Chapter 5, "Food and Food Finding", discusses feeding behavior and food habits
for many taxa of carnivores. Not only docs the author i)rovide data at the family
level, in many instances she supplies detailed accounts at the species level.

A discussion of signals and social oi'ganization (Chapter G) logically precedes a
chapter on social organization and living space (Chapter 7). Together these chapters
provide an interesting account of the social life and l)ehavior of the Carnivora. These
chapters, like most of the others, present the material in a comparative manner, a
technique particularly appreciated by the reviewer. In Chapter 8, reproduction is
broken down into general biology, courtship and mating, and development and
rearing of the young. In each category, the author again discusses the different
aspects at the family level as well as at the generic or specific level when d;ita are
sufficient to allow it.

Chapter 9, "Fossil Relatives", briefly discusses the early relatives of the present
day Carnivora. and presents data on the origins and relationships of the living
families. Included is a necessarily brief treatment of the biochemical relationships
of the living families as well as a discussion of some karyological dat.-i and their
implications regarding the evolution of the present day Carnivora. A useful table
detailing the diploid chromosome numbers of many genera and species, representative
of all extant families, is included.

( 255 )

256 CALIFORNIA FISH AND GAME

Chapter 10, "Classification and 1 )istiilinti(in of tlic I-ivin;; Species", is a syste-
matic and zoogcographic review of tlie extant ('arni\ora. Tiic antlior points ont
many of tlie taxonomic problems inherent in a j;roMi) as lar^'t- an<l diverse as the
Carnivora and includes, at pertinent points, her own opinions. Of particular interest
is Ewer's treatment of the Felidae ; however, she is in agreement with Leyhausen
(Bull. Zool. Nomencl. 2.j :lo(), 10G9), that a satisfactory dassifieation will i)e possi-
ble only after each and every species of cat has been tli()r()u;,'lily studied.

This work cannot be considered complete in its treatment of carnivore biology.
It is particularly weak in its treament of physiology and population dynamics,
subjects which are scarcely mentioned. The Carnivores is, however, a useful, well-
written and intriguing account of many of the aspects of carnivore biology, and will
be a welcome addition to the lii)raries of interested biologists and naturalists.
Although some obvious errors and omissions occur, the author has presented in one
volume a usable, i*eadable compilation of pertinent facts and opinions. It is un-
fortunate that the publisher has seen fit to place such an exorbitant price on this
^•olume. — ^'er)wn C. Jileich.

fly Casting with Lefty Kreh

By Lefty Kreh; J. B. Lippincott Company, Philadelphia and New York, 1974, illustrated.
$8.95.

Fly casting has often l)een a major obstacle which discourages people and keeps
them from taking up the sport of fly fishing. Instead, they look for an easier and less
complicated method and fall back on the spinning rod. I don't look for this new book
on casting by Lefty Kreh, however, to make great inroads into the problem. The old
Chinese philosoi)her who once said "one picture is worth a thousand words" must
never have attempted to teach a tyro fly caster the art of forming a neat, tight,
wind-cutting loop with 30 feet of fly line. Photographs, diagrams, or silhouettes can
never convey the idea of timing and rhythm.

This book uses a series of sequence photos of Lefty in \arious positions of casting
and creates an artful approach to .solving the problem. By carefully using light and
shade in his photos. i)hotograi>her Irv Swope has made Lefty's rod and fly line glow
as though lighted with electricity. The reader can follow the sequences through and
gain an idea of Lefty's movements during casting. AVhile the casting style is fairly
basic, it does differ somewhat from traditional form. The author has incorporated
several tricks develoi)ed by West Coast fly fi.shermen for big, windy steelhead rivers.

In conclusion, while Fh/ Casting irifh Lefti/ Kreh is not intended to turn every
fly caster into another Steve Bayjeff (World Chami)ion Fly Caster), it does approach
a difficult problem in a manner easily understood by the beginner. — Dennis I'. Lee.

How to Tie Freshwater Flies

By Kenneth E. Bay; Winchester Press, N.Y., 1974; vii -f- 152 p. color and black-and-white
photos. $10.00.

It's always fun to watch a fly tier at work and reading Ken Bay's book "How to
Tie Freshwater Flies'' is just like sitting next to an experienced tier and watching
him tie.

This is a book for the beginner and by far the best book available for someone who
has never tied before and wants to teach himself. There are initial brief cliapters on
fly tying tools, hooks, and materials. While the chapters are brief, they do present
the basic information needed by a beginner and present it in a clear, straight-forward
style. The r<'mainder of the liook" is the "how to" i)art. detailing first the basic
techniipies of tying the thread on the book, tying in tails and various wing materials,
and, finally, the whip finish. Each step of each process is clearly illustrated in large,
black-and-white photos by Matthew Vinciguerra. The final four chapters photograph-
ically lead the reader through the stejis of tying 14 different iiatterns. including 12
streamers, 2 wet flies, 7 dry flies, and '\ nymphs. Eadi iiattern was obviously chosen
to illustrate the techni(iues recpiired f(U" different materials, but each i);ittern is a
good, fishable pattern. One brief appendix provides a .selected bibliography and a list
of sources of fly tying materials.

The book has few, if any, shortcomings. I would have included i)hotos of hackling
both wet and dry flies in the chapter on basic techniques, and I think tlu' book could
have been further improved by ji bit more exjilanation of uhi/ a technique was )ised
— AVhy are spent wings tied spent'.' AVhy do you tie in materials under the shank
of the hook? A more detailed explanation of proportions and position of wings, tails,
etc. would have also added to the text.

REVIEWS 257

The photos are excellent and the inclusion of 4 color plates of materials and the
finished fly patterns really improve the hook. It's well worth the .$10 price tag.
— K. A. Hashagen, Jr.

Return to the River

By Roderick Haig-Brown; Crown Publishers, Inc., N.Y., 1974; 248 p. black-and-white illustra-
tions. $7.50.

Long out of print. "Return to the River" has finally been reprinted, to the delight
of many angler/readers familiar with Haig-Brown's worl< and for the enjoyment of
those who have yet to discover Haig-Brown.

The subtitle of the book is "The Classic Story of the Chinook Run and of the Men
Who Fish It". The book describes the life history of a Chinook salmon, "Spring"
from the time of egg deposition to her eventual spawning and death. There is a huge
mass of authentic, accurate life history information presented in a very enjoyable,
fictionalized manner. The author obviously knows his salmon and has read the tech-
nical fisheries literature extensively. No a.spect of the life cycle of a .salmon in the
great Columbia River system is missed — spawning, predators, prey, pollution,
logging, dams, offshore migrations, commercial and sport fishermen, hatcheries.

The book is a classic and I highly recommend it to any one interested in fishing
and the literature of fishing. The price is $7.50. — A'. A. Hashagen, Jr.

Trout Magic

By Robert Trover; Crown Publishers, Inc., New York, 1974; 216 p., black-and-white illustra-
tions. $7.50.

Crown Publishers continues to turn out top quality fishing books — this one is a
book of short stories by Robert Traver, author of "Trout Madness" and several other
books. Over half of the 17 stories have appeared elsewhere but they're all worth
reading or rereading. I spent a couple of very pleasant evenings reading "Trout
Magic". The illustrations by ^Milton Weiler are very nicely done and add a lot to the
book. — K. A. Hashagen, Jr.

Wilderness Fishing for Salmon and Steelhead

By Roy A. MclnturfF; A. S. Barnes and Co., New Jersey, 1974; 197 p., illustrated. $8.95.

Roy Mclnturff, the author of ""Wilderness Fishing for Salmon and Steelhead"
has been enthusiastically fishing the Klamath and Trinity rivers in California each
fall for the last 20 years. Unfortunately, he felt it was necessary to write a book
about his experiences. While you have to admire his love of these rivers and his
enthusiasm for salmon and steelhead fishing, you Avonder how anyone could put
together a book like this one. There is a fair amount of misinformation on move-
ments of fish and the life history information, there are numerous typographic er-
rors, which detract from the text, and one photo is used three times, once on the
cover and twice in the book itself. Although fishermen rarely agree on tackle or
techniques, most will agree that night crawlers are not a "new" bait for steelhead,
and that monofilament can be used successfully for shooting line on fly rod ; the
author has to l)e the only i)erson I know who has been fishing for any length of
time who uses a spear point barbed eyelet to attach his leader to his fly line. His
views on conservation are stated roughly as follows "Keep all you catch — if you
can't use 'em you can always give 'em away" and "A few small 'trout' taken
on a small fly make a good breakfast if you can't catch a steelhead". Sorry, I just
can't recommend this one. — A'. ,4. Hashagen, Jr.

The Trout and the Stream

By Charles E. Brooks; Crown Publishers, Inc., N.Y., 1974; viii -|- 216 p., illustrated. $7.95.

For anglers who make the pilgrimage to the rivers and streams of Idaho, south-
western Montana and northeastern Wyoming this book will have far more value
than to those unfamiliar with these waters. Mr. Brooks tells about habitat, fish,
fishing techniques, tackle, and conservation using as examples the Gallatin, the
Madison, the Firehole, the Yellowstone, and Henry's Fork of the Snake.

258 CALIFORNIA FISH AND GAME

Tlio first fhaiitcr "Life in Utiiiiiiii;; Wjitci-"' is .1 scmidis.-istcr, <lrsfril)iiiK the
intcrrt'liitioiiships and interactions of al^ao, piivto- and zooplankton, and oth<T food
orKJinisms as well as temporatnre, oxygon, and tiie cliPinical composition of the
water. The presentation of the material is awkward and often confnsint;. Mr.
Urooks lias sjxMit a fireat deal of time collecting;, observing, and formnlalin^; theories,
many of which, lie says, he was hapi)y to find confirmid l)y professionals like Bir;;*'
and .Tuday. Needham, Kuttner, and llynes. I feel there is far more in this section
tiian the average fisherman wants or needs to know and insnflicient detail for the
student or professionjil.

The remainder of the l)f)ok is far hctter. Mr. Brooks is predominantly a nymph
fisherman and iis such has sjient many yeai-s collect in;;, identifying. f)hserving hoth
above and l)elow the water's surface, thinking, and experimenting. He i)uts it all
together very nicely — rods, lines, tippet size, retrieves, patterns, water types. It
makes interesting reading, iind even if you don't agree Avith all of it 1 think most
fishermen will find something new to experiment with or at least think almut.

There is the usual chapter on fly patterns and how to tie them, which would be
of value to anyone planning to fish the Yellowstone area waters. There is also a
chaiiter on conservation, which must he required by law in all recently published
fishing books — tlie release your fish, get involved, don't litter i>hilosoi)hy.

All in all "The Trout and The Stream" is an interesting, entertaining book. The
price (.$7.0r>) is reasonable and the illustrations by Dave "Whitlock are good. — K. A.
Ifdshagcn, Jr.

A River Never Sleeps

By Roderick L. Haig-Brown; Crown Publishers, Inc., N.Y., 1974; 352 p., illustrated. $7.50.

It has been a long time sinc>» I have enjoyed a fishing book as much as I enjoyed
"A River Never Sleeps" by Roderick II;iig-Brown — probaiily not since I read an
earlier edition of this same book. Crown Publishers has done fislu'rinen/readers a
great service by rejjrinting this long out of iirint classic. It is a Imnk to lie read
slowly and savored thoroughly.

"A River Never Sleeps" was written "simply to define and pass on some of the
pleasures I tllaig-Brown) have had from fishing". Basically, it is a book about
rivers and changes in the ri\ers and fish throughout the course of a .vear. How-
ever, that is i)utting it far too basically and l)luntly. The river is any river — from
English rivers from the iuithor's boyhood to the Campbell on Vancouver Island. It
isn't all about rivers, though ; there is also mention of lakes, estuaries, and the
salt water. The fish are salmon, steelhead. cutthroat and lirown trout, pike, and
chubs. There are stories of liunting, of family, and of the out of doors. Stories of
fishing in British Columbia cover the si>an of time, roughly from l!>li.") to 194."i.
There arc wonderful glimpses of the abundance of fish and wildlife of that period.
No mention is made of vast numbers of competing anglers. In discussing the life
and death of salmon, the author mentions tlie man,\- species of i)irds ;ind m.-nnmals
utilizing the dead and dying fish. He counted li(M) Icild eagles in a 12-mile stretch of
river — I wonder what it would be today.

This book I can highly recommend. The price is reasoiiable and the writing ex-
cellent. Haig-1'rown is a far better observer of his surmundings than the average
tislieiMuan and. fortunatel.v. is iiii extremely articul.-ite writei". A. .1. II (isIkukii. Jr.

The Shore fishes of Hawaii

By D. S. Jordan and B. W. Evermonn; Charles E. Tuttle Co., Rutland, Vermont, 1973; 392
p., illusfrafed. $8.50 paper.

In a chapter entitled "Introduction to the new edition," the reader is informed
that "This classic study of Hawaiian shore fishes was first in-inted in Washington
in '\*,)()r} . . . [and] is .-in abridgment into h.andbook form, imw newly titled The
Shore /•'i.v/ic.v of llairnii." Further. "In condensing this iiKunnnn opuK of Hawaiian
iciithyology the editors Inn e omitted only those parts of little reference value today
to the fisherman, scub.i divers, fi.sh fanciers, or other readers who are likely to use
the book. The deleted ]iarts relate mainly to nineteenth-century literature, his-
torical background, and other data of scant contemporary interest."

REVIEWS 259

An examination of the 574-page 1905 edition, shows that 28 pages of historical re-
view and bibliography have been omitted, as well as 7 pases on introduction of addi-
tional species (to Hawaii) and 1 page of addenda. In my opinion the editors
showed extremely poor judgement in failing to reproduce Jordan and Evermann's
The Shore Fishes in its entirety. Contrary to their belief that this information is
"of scant contemporary interest," I feel that a great void was created by failing
to include these relatively short but extremely pertinent sections.

The original pagination has not been retained in the present abridgment and
the 138 plates (73 color and C") black and white) which were scattered through-
out the 1005 edition are now condensed onto 32 pages at the back of the book.
Typescript and black-and-white figures have reproduced beautifully, but the color
reproductions leave much to be desired. It is unfortunate that the editors did not
include an addendum listing the currently accepted scientific names for the included
taxa, especially generic and specific names. It .seems to me that those who supposedly
are to benefit from the present abridgment (i.e., fishermen, scuba divers, fish fanciers,
and lovers of nature in general) truly would have benefited with up-to-date nomen-
clature. One can't fault the price, however. — John E. Fitch .

Marine Molluscan Genera of Western North America: An Illustrated Key (second
edition).

By A. Myra Keen and Eugene Coan; Stanford University Press, Stanford, Calif.; 1974,
vi + 208 p. $8.75.

When the first edition appeared in 1963, it was so well done that I thought it
would be two or three decades before it could be improved upon substantially, yet here
in just 11 years is a greatly improved version. Text and keys have been completely
revised and reset, and the page size has been reduced "to make the book more
portable."

An expanded "introduction" briefly explains the logic involved in classifying and
identifying living organisms, and fits mollusks into the orderly world of marine
invertebrates. The history behind, and layout of, the present book are also explained.
The four figures illustrating gastropod topography and terminology now appear on a
single page which faces a page showing the 11 basic shell forms. An idea as to the
expanded coverage can be obtained by looking at the first couplet in the gastropod
key : in the first edition the opposing characters in this couplet referred the user
to couplets 2 and 3G ; in the present edition, one is referred to couplets 2 and 43. In
both editions, Cryptogemma is the last gastropod genus keyed-out ; however, in the
first edition it is with couplet 235, while in this edition it is with couplet 262.
Similar expanded coverage is found in all keys except that for cephalopods, and a
key to families of Aplacophora is presented.

An innovation with this edition is a chapter entitled "Identification of figures"
which gives generic and specific names, and authorities and dates for the shells
figured in the keys.

Surely now we have an edition that is so meticulously prepared, and so complete
that I do not see how it can be impi'oved upon in this century, at least. — John E.
Fitch.

Seashore Life of Puget Sound, the Strait of Georgia, and the San Juan Archipelago.

By Eugene N. Kozloff, University of Washington Press. 310 pp. 28 color plates, 223 draw-
ings and black and white plates. Cloth — $15.00; paper — $6.95.

Although Dr. Kozloff, an outstanding marine ecologist, designed this book
specifically around the inner Pacific Northwest region, about 90% of the plants and
animals discussed are commonly found in the temperate nearshore waters as far
south as Point Conception.

The book is written primarily for amateur and student naturalists and the first
47 pages are dedicated to Avhat the author calls "instant zoology and botany" where
tides, the metric system, and taxonomy are explained. A much needed "plea for
conservation" with 10 rules of seashore etiquette is also offered. A bonus to the
novice is a 105 entry glossary of common marine biological terms. However, be-
cause of its many plates and up-to-date taxonomy, the book also makes a handy,
although limited, secondary reference for working field biologists.

The material is divided into three habitat types : Floating docks and piers, rocky
shores, and sandy beaches and quiet bays — another feature geared to the needs of
beginning and amateur biologists. The great strengths of the book are the large
amount of natural history it contains and, refreshingly, that the plates of plants and
animals usually appear on the pages where they are discussed.

260 CALIFORNIA FISH AND GAME

The book is not Avithout flaws and my major criticism is that the glued softback
binding of the paperback version appears inadeqiiate for a lot of field use. Hopefully,
the cloth back is better suited for this purpose. Although most of the plates are ex-
cellent, a few of them (in my copy) reproduced very poorly and some could have been
better chosen. Despite these criticisms, this is an excellent book which belongs in the
collection of anyone interested in marine natural history. — Laurence L. Laurent.

The Blackbass in America and Overseas

By William H. Robbins and Hugh R. MacCrimmon; Publications Division, Biomanagement
and Research Enterprises, Sault Ste. Marie, Ontario, Canada, 1974; 196 p., $12.95
(hardcover) $7.95 (softcover).

The authors have condensed a tremendous amount of information into 196 pages.
It must have been a labor of love to compile the information gleaned from several
hundred sources into so compact a form.

A brief account is given of the discovery and scientific description of the six spe-
cies of blackbass that are currently recognized. Taxonomic descriptions and a key to
the six species are provided.

Each species is covered in a separate chapter, all following the same outline : a
review of its biology, its native and naturalized (if any) range and its status as
a sport and food fish. This similarity in format makes it easier to compare dif-
ferent aspects of the various species.

Space is allotted each species roughly in relation to its native range, with the
largemouth and smallmouth bass getting top billing, since they are the most widely
distributed and well known. The restricted range of the Guadalupe and especially
the Suwanee bass has kept them from the eye of the public and scientists until
quit recently, which no doubt accounts for the limited space allotted to them. The
authors cite only three references for the Suwanee bass.

A brief history is presented of the culture of the blackbass in North America, as
well as present ISTorth American and world culture.

The chapter on the habitat requirements of the six species of bass neatly sum-
marizes their requirements for a quick reference for the fishery manager who is on
the lookout for a game fish to fill a particular biological niche.

The chapter on angling for blackbass is not a "how to" guide, as the title may
imply, but a very brief "where to" for the Americas, Eurasia and Africa.

One of the most valuable chapters in the book is the biltliography. which lists 504
references, 144 personal communications that are cited in the text, plus 61 addi-
tional personal communications that were not cited.

I may be picky, but the only fault I could find with the book is in the illustra-
tions. I particularly found the distribution maps to be difficult to comprehend,
primarily due to too much detail. The quality of the photographic illustrations is
generally quite good, even though I personally am not fond of the montage-like pres-
entation of many of them.

All in all, this is a handy reference book tliat any fishery biologist who is working
with blackbass should find valuable. — D. A. La Faunce.

Fisherman's Spring

By Roderick L. Haig-Brov/n; Crown Publishers, Inc., N.Y., 1975; 222 p., illustrated. $7.50.

Crown Publisliers, Inc. continues to do anglers/readers a great service by reprint-
ing another Ilaig-Brown angling book. Fisherman's Spring, first published in 1951,
is the first book of a four-book series chronicling the four angling seasons of the
year.

Written in Haig-Brown's usual rambling, philosophical style. Fisherman's Spring
discusses early season angling, starting with the opening of British Columbian
trout season. The book doesn't just talk about fish and fishing, but the whole fishing
experience — gear, canoes, wading, flies, family, and birds. Throughout the book
there is a strong conservation message. The books being published today beat the
drum loudly for conservation ; Haig-Brown saw the need for gear and bag restric-
tions over 20 years ago. He discusses the role of forests and the need for sensible
logging practices.

Although not a trained biologist, the author is a very observant fisherman and a
thinking fisherman. Above all he is an excellent writer. I highly recommend Fisher-
man's Spring, as I have all Haig-Brown's other works. — K. A. Ilashagcn, Jr.

ERRATA

Crano, Julos M., Larry G. Allen and Connie Eisemann. Growth
rate, distribution, and population density of tlie northern quahog
Mcrccnaria mcrccnaria in Long Beach, California. 61 (2) : 68-94. 1975.

Tables 1, 2 and 4 : replace x with x.

Table 3 : units are in mm.

Table 4 : Cage 3, size class 61-80 should read 5.0.

Figure 4, replace scale : 1 cm = 31 m.

Page 79, paragraph 6, line 2 : delete since.

(261)

INDEX TO VOLUME 61

AUTHORS

Allen, Larry G. : see Crane, Allen and Eiscmann, G8-04

Anderson, M. Eric and Grogor :M. Cailliet: Occurrence of the rare Nortli I'acific

frostfish, BenthodesnuiH cloiKjatiis pncificus Parin and Becker, 1970, in INIonterey

Bay, California, 149-152 ; see Cailliet and Anderson, G0-C)2
Andreasen, James K. : Occurrence of the fathead minnow, Pimephales promclas, in

Oregon, 155-150
Bertram, Ronald C. : see Rempel and Bertram, 237-239
Burton, Timothy S. : see Piekielek and Burton, 4-25
Cailliet, Gregor M. and ]M. Eric Anderson : Occurrence of the prowfish. Zaprora

silenus Jordan, 1890 in Monterey Bay, California, 00-02; see Anderson and Cail-
liet, 149-152
Campbell, Gail and Rohson A. Collins : The age and growth of the Pacific bonito,

Sarda chiliensis, in the eastern North Pacific, 181-200
Clark, Patrick, James Nybakken and Lawrence Laurent : Aspects of the life history

of Trestis nutfaHii in Elkhorn Slough. 215-227
Collins, Robson A. : see Campl)ell and Collins, 181-200
Courtois, Louis A. : Blood and serum analysis of adult striped bass captured in the

Sacramento River, 245-240
Crane, Jules M., Larry G. Allen and Connie Eisemann : Growth rate, distribution,

and population density of the northern quahog Mercenaria mercenaria in Long

Beach, California, 08-94
Crase, Frederick T. : .see DeHaven, Crase and Woronecki, 100-180
DeHaven, Richard W., Frederick T. Crase and Paul P. Woronecki : Breeding status

of the tricolored blackbird. 1909-1972, 100-180
deWit, Leray A. : Changes in the .species composition of sharks in .south San Fran-
cisco Bay, 100-111
Dinnel, Paul A. : see Quirollo and Dinnel, 150-157
Duffy, John M. : A range extension and two new California size records for mollusks,

152-155
Eisemann, Connie : see Crane, Allen and Eisemann, 08-94
Espinosa, F. A. Jr. : see Paulson and E.spinosa, 209-214
Eldridge, Maxwell B. : Early larvae of the diamond turbot, Ifijpsopsetta guttulata,

20-34
Fry, Donald H. : Measuring salmon, an old and unfamiliar method, 247
Gall. G. A. E. : see Gold and Gall, 248-250
Gold, J. R. and G. A. E. Gall : Further record of the Little Kern golden trout.

Salmo af/itnhoiiif(i irJiitci in the Tiittle Kern River Basin. California, 248-250
Green, Roger E. : A preliminary list of fishes collected from Richardson Bay, Cali-
fornia 1972-1973, 104-100
Hauser, William J. : An unusually fast growth rate for Tilapia !:iUii, 54-50
Hensley. Gary II. and F. ^M. Nahhas : Parasites of fishes from the Sacramento-San

Joaquin Delta. California, 201-208
Hobson, Edmund S. : First California record of the serranid fish Anthias gordensis

Wade. 111-112
Knaggs, Eric H., .John S. Sunada and Robert N. Lea : Notes on some fishes collected

off the outer coast of Baja California, 50-59
Knight, Allen W. : see Kost and Knight, 35-40
Kost, Angela L. Blado and Allen W. Knight: The food of Xeomj/sis mcrccdis Holmes

in the Sacramento-San .Joaquin Estuary, 35—40
Laurent, Lawrence : see Clark, Nybakken and Laurent, 215-227
Lea, Robert N. : see Knaggs. Sunada and Lea, 50-59
Mathews. C. P. : Note on the ecology of the raffish. Ilydrolagus coUei, in the Gulf

of California, 47-53
McCullough, Dale R. : Modification of the Clover deer trap, 242-244
Mearns, Alan J.: Poeciliopsis gracilis (Heckel), newly introduced poeciliid fish in

California, 251-2,53
Odenweller, Dan B. : An unusual aggregation of bat rays. Mijliohatis californica

Gill, 159
Nahhas, F. M. : sec Ilen.sley and Nahhas. 201-208
Nybakken, James : see Clark, Nybakken and Laurent, 215-227

(203 )

264

CALIFORNIA FISH AND GAME

Paulson. Larry J. and F. A. Espinosn, Jr.: Fish trappinR: A now motluul of ovnln-

atinjr fi.sh species composition in limnetic areas of reservoirs. 20'.Vlil4
Piekielek. "William and Timothy S. Burton : A black hear population study in north-
ern California. 4-2."
Quirollo, Lawrence F. and I'aul A. Dinnel : Latitudin.il raii^'c extensions for yellow

and spotted .snake eels (genus Ophichihus) . l."0-l."7
Rawstron, Robert R. : Mortality and growth rates, cost, and relative contribution

of two different sizes of silver salmon stocked in Lake Rerryessa, California, in

1972. 127-132
Rempel, Ronald D. and Ronald C. Bertram: The Stewart modified corral trap. 237-

239
Russo, Ronald A.: Notes on the external parasites of California inshore sharks.

228-232; Observations on the food habits of leopard sharks (Trinkii> srwifascinln)

and brown smoothhouuds (Mustclxs Jiciilci) , 95-103
Schott, Jack W. : Otter trawl cod-end escapement experiments for California haliljut,

82-103
Spratt, Jerome D. : Anomalous otoliths from the northern anchovy. EngrauVix mor-

dax, 23.'j-2,3G ; Growth rate of the northern anchovy. EngrauVnt mordax. in south-
ern California waters, calculated from otoliths, 110-1 2G
Sunada, John S. : Age and length composition of northern anchovies. EngrauVix

mordax, in the 1972-73 season, California anchovy reduction fishery, 13.3-143;

see Knaggs, Sunada and Lea. .'"i0-.'")9
Talent, Carline L. : .sec Talent and Talent. 233-234
Talent, Larry G. : A parakeet anklet, Gi/clorrhynchus psiftaculn. from ^lonterey

Bay, California, LIS; Pugheadedness in the longspine combfish. Zfiiiioleins Infrpin-

tiis. from Monterey Bay. California, 1G0-1G2
Talent. Larry G. and Carline L. Talent: An extrauterine fetus in the Steller sea

lion, Eumetopias juhnta, 233-234
Thomas. Ronald D. : The status of Rocky Mountain elk in Kern County. 1974, 239-

241
White, Robert L. : Polymorphism in populations of !^eeIoporiis occidentalis in Santa

Barbara County. California. 2r)3-2.")4
"Wilbur, Sanford R. : California condor pluniiige and molt as field study aids. 144-148
AVinfersteen, .Tohn : Occurrence anil depth range <'xtension of the yellow snake eel,

Ophichthus zophochir. off southern California. 1.57-ir)S
"Woronecki, I'aul P. : see DeHaven, Crase and AVoronecki, lGG-180

SCIENTIFIC NAMES

Acanthoiiiijsis sculpfa: 4~>

Accipifer genfilis: 14."

Acer vincropJn/Uus: G

Acipoiscr lucdirostris: 2()G

Acipne.seridae : 20<1

Aegypius nioiiachus: 14G

Agoiiopsis stcrlctus: 58

AUoglossidiioii corti: 201 ; 204

Alosa sapidissiina: 201 ; 2a")-20G

Anchoa exigua: 57

Anoplopoma fimhria: 58

Anthias gordensis: 111

Anthids sechunie: 111

Apohjmctis hiaiigulatu : 72

Aqelaius tricolor: IGG

Aquila chnjsnefos: 14G

Arhutus luoizirsii: G

Arcfostaphi/lns pafuJa: G

Arctostaphglos vi.'<cida: G

Arculatala demissa: 72

Aruiido doiinx: 172

Athcrinopsi.H cdliforniciisis : 110

AthrriiiopsiH sj). : 101

Atrdctolytoccstus hiiroiicnsis: 201. 204-

205
lienthodesmus clongatus pacificus: 149—

150

lUulhodesDtus simony i: 149

lieiifhodeswus sp. : 149

Jirassicd cunipcstris : 172

Jlotlirioccplidliis cldricrps: 201 ; 205

BrancheUion lohdia: 230-231

liranchellion sj). : 2.30

Calliandsd californiensis: 99

CdUidudsd sp.: 99. 102

Cancer productus: 99

Cancer sp. : 99

Capillaria calenata: 201 ; 205

Cdrdssiiis diiralus: 201. 20.5

('(irtlidniiis tinrtoriiis: 172

Catostoiiius riniicuhis: 1.55

Cenfatirea sp. : 172

Cera fi inn sp. : 44

Cerviis canddensis canadensis: 239

Cestoda: 201. 204

Chaenohrytius guiosus: 201 ; 204

Chione fluctifraga: 72-73

Chione iniddfcUa: 72

Cblorophyta : 44

Chroinis punctipinnis: 111

Ciona iniesiinalis: 72

Ciiharichthys sp. : 100

Clcidodiscus pricei: 201 ; 204

Clevelandia ios: 100

INDEX

265

Clinocardimum naltalU: 215

ClinostomiDii marginatum: 201, 204

('lupca harcngus pallasi: 101

Cliipeidac: 20G

Confracaecum hrachyunim: 201, 20G

('oiitraraccinn xpiculigcniiii : 201, 206

('oraUubothriiiiii finihiial inn : 201, 20."»

Corallohothriiim gigaiitcinii : 201, 205

Coniua iiuttaUii: G

Coscinodiscus sp. : 40—42

Tottidac : 20G

('ottiis gulosus: 20G

Crago francisconnn: 09

ri-ustacea: 201, 20<>

( "rytophyta : 44

( "yanophyta : 44

Vyclorrhynchus psiifacuhi: 158

CycloicUa sp. : 41

Cymaiogasier aggregafa: 100

Cynoscion nohilUs: lOG

Cypriiiidae : 207

Cypriiiodon macitlariiis: 252

Cyprinus carpio: 201, 20.3-205, 252

Daclylogyrus cxtensiis: 201, 204

Dif^cnea : 204

Dorosonia cepedianuiii: 209

Dorosoma petenense: 20G, 209

Echihrogaleus coleopiratus: 229

Embiotocidae : 207

EngrauUs mordax: 100, IIG, 133, 182,

235
Enteromorpha iiitcstinalis: 72
Enier'omorpha sp. : 72, 79
Eniosplienus iridenlaius: 155
Epinephelus niveatus: 58
Epfatretus stoutii: 5G
Eumetopias juhata: 233
Florimetis ohesa: 72
GalcorJiiiius ~yopterus: 110, 228
Gamhusia affinis: 251
Gari calif ornica : 153-154
Gymnogyps calif ornianus: 144
Ilaliaeetus leucoccphaJits: 14G
Hemigrapsus nvdiis: 99
Jleinigrapsus oregonencsis: 99, 110
Hemigrapsus sp. : 99
Ileicrandia pleurospilus: 251
Ilexanchus griseus: 57
Ilinidinea: 201, 20G
Ilydrolagus collei: 47, 57
Hydrolagus sp. : 57
Hypsopsetta guttulata: 2G, 33
Hypsopsetta sp. : 2G, 33
Hysterocarpus traskii: 207
Icfalurus catus: 201, 204-20G
Iciahirus melas: 201, 205
Ictalurus uehulosus: 201. 204, 20G
TctaJurus punctatus: 201. 204-205
JlJinohdeUa alba: 20G
UlinohdcUa clongaia: 20G
lUinohdella moorci: 201,20G
Illinohdella richardsoni: 20G
lUinohdella sp. : 20G
Keraiella sp. : 44
Khaicia ioicensis: 201, 205
Lacistorhynchus sp. : 201, 205

Laevicardium datum: 72

Lavinia cxilicauda exilicauda: 207

Ijcpomis cyanellus: 205

Lcpomis macrochirus: 201, 204-205

Lerhaea cyprinacaca: 201, 20G

ryerneopididae : 229

Lerneopoda scylicola: 229

Liboccdrus dccurrens: G

Lycodopsis pacifica: 158

Melosira sp. ; 40-42

Mcrcenaria merccnaria: G8, 72-74,

78-80
Mercenaria sp. : 72-74, 78, SO
Metabronema salvelini: 201, 20G
Microstomus pacificus: 59, 158
Molgula manhattcnsis: 102
^Nlonogenea : 204
Morone saxatiUs: 35, 110, 201, 204-206,

245
Mustelus henlei: 95, 228
.¥2/0 arenaria: 217
Myliobatis calif ornica: 100, 159
Mylopharodon concocephalus: 201, 206
My sis relicta: 45
Mytclis edulis: 72
Myxololus cyprinicolo: 204
Myxobolus cllipsoides: 204
Myxobolus koi: 201, 204
Myxobolus sp. : 203-204
Myxobolus ioyamai: 204
Xematoda : 201, 205
Neomysis integer: 45
Neomysis mercedis: 35, 40, 44
Neomysis sp. : 45
Notemigonus crysoleucas: 207
Notorhynchiis maculatus: 100, 110, 228
Xotropis liitrensis: 251
Octopus sp. : 102
Odocoileus virginia)ius: 242
Oncorhynchus kisutch: 127
Oncorhynchus tshatvytscha: 6, 18, 207
Ophichthus sp. : 156
Ophichthus triserialis: 157
Ophichthus zophochir: 156-157
Orthodon microlepidotus: 201, 206
Pachygrapsus crassipes: 99
Pandaris hicolor: 228-229
Puralichthys californicus: 82
Paraniysis arenosa: 45
Parophrys vetulus: 58, 85
Pediastrum sp. : 44
Pelichnibothrium spcciosum: 201, 205
Perissopus oblongatus: 228-229
Philometra carassii: 201, 205
Philometra sanguinea: 205
Philometra sp. : 205
Philometra triliabiata: 205
Physiculus rastrcUigcr: 57
Pimephales promelas: 155-156
Pinnipedia : 233
Pinus lambertiana: 6
Pin us pondcrosa: 6
Pinus sabiniana: 6
Piscicolidae : 230
Platichthys sfeUatus: 207
Pleiironectidae : 207

266

CALIFORNIA FISH AND GAME

Pleuyonichthys cocnosus: 33
I'leuroiiichthi/K dccunciis: 20, 33
Plcuroitichthijs sp. : 20, 33
I'Iciirouichtln/s vcrticalis: '2C>. 33, 83
I'oeciUa lotipinna: 2."i2
I'oeciliopsis gracilis: 2.'>1-2.j3
Poeciliopsi.s iiicxicaiia: 251
Pocciliopsis occidoifalis: 2.")!
I'occilislcs piciirospilii.- : 251
Pogonichthys macrolcpidotus: 201
Pogonichthys macrolcpidotus: 200
Poiiioxis nigromncuJatus: 201, 200, 211
Porichthys'notatux: 'JO, 100, 158
Posthodiiilosfohiinii iiiiiiiiinnii rciitrarchi:

201, 204
Prion ace glauca: 229
Profoihaca sfnwinca: 72-73, 153. 215
Protozoa : 201

Pscltichthys inchuioslictus: 85
Pseudotsuga )iu)i~iesii: 0
Ptychocheilus grand is: 201, 20G
Qurrcus gar ry an a: 0
Qucrcus kclloggii: 0
Quercus irisUzenii: 0
/>'«;■(; hinoculata: 220
7?ayfl irachura: 106
Raphidasraris sp. : 201. 200
Rliinichthys oscuhis: 155
liuhus sp. : 172
«?a?i.r sp. : 171
Salmo agiiahonita: 248
Saliiio agiiahonita aguahonita: 248, 250
Saliiio (Kiiiiilionitd irhifci: 24S
.Sn/wo gairdneri: 127, 155, 207, 248,

250
Salmonid.ic : 207
Sard a chilicnsis: 181
Sardinops sagax cacrulcus: 110
Siaj-idoinus nuttaUi {= S. nuttallii) :

153
Saxidomus nuttallii (= <S'. nuttaUi) :

215
Sceloporus occidental is: 2.53-254
Sceloporus occidcn talis hiscriatus: 2.53
Sceloporus occidciitalis hocourti:

253-254
Sceloporus occidcn talis longipcs:

253-254
Sceloporus occidentalis occidentalis: 253

Scencdesmus sp. : 44

Schistomysis spirit is: 45

Schizothacrus nuttali: 101

Schizothacrufi sp. : 101. 215

Scirpus sp. : 171

Sconiher japonicus: 125, 182, 188

Scylliuni sp. : 229

Semele decisa: 153-154

Spiroxys sp. : 201, 200

S(iualus acantliias: 100, 228

St/uatina californica: 230

Stcreolcpis gigas: 57

Styella plicata: 72

Ni//r; hassana: 14.5

Syinitliurus atricauda : 158

Tahcllaria sp. : 43

Tagclus calijornicus: 72

Terchra pedroana: 152, 154

Tilapia mossanihica : 252

Tilapia sji. : .54, 252

Tilapia zillii: 54—55

Trachurus synnnetricus: 182

Tresus capax: 215, 220

TrcSKS nuttaUi {= T. nuttallii) : 153

2'rcsH.s nuttallii {= T. nuttalli) : 215,

221 220
r;T.'?«,'( sp. : 215, 219, 220
Trematoda: 201
Triakis scmifasciata: 95, 228
Triccratium sp. : 43
Typha sp. : 171
r^ra lohata: 72
Upogchia pugcttensis: 99
Upogehia sp. : 99, 102
Urcchis caupo: 101
Urechis sp. : 102
Ursus americanus: 4
TJrtica sp. : 172
T'K//wr gryphus: 140
Xiphophorus helleri: 252
Xiphophorus variatus: 252
Xystrcurys liolcpis: 83
Zaniolepis frcnata: 58
Zaniolrpis latipinnis: 58. 100
Zaprora silcnus: GO
Zaprora sp. : 01
Zostera niarina: 101

SUBJECT

Age : of Pacific bonito in eastern North Pacific, 181-200

Age composition : of northern .■inchovies in the 1972-73 season California anchovy

reduction fishery, 133-143
Analysis: of blood and serum of aduK stripeil bass captured in Sacramento River,

24.5-240
Anchovy, northern: iige and length composition in the 1972-73 season California

anchovy reduction fishery, 133-143; anom.'ilons ntoliths in, 23.5-230; growlh rate

in southern California waters, 110-120
Anehovy reduction fishery: age and length conip"^it ii"i "f northern anchovies in,

l!t72-73, 133-143
Areas, limnetic: evaluating lish species composition in reservoirs by fish trapping,

209-214
Auklet. parakeet: found near Monterey Bay, 158
Bass, striped : analysis of blood and serum of adults captured in Sacramento River,

245-24G

INDEX 267

Bear, black : a population study in northern California, 4-25

Blackbird, tricolored : breeding status, 1969-1972, 16G-180

Bonito, Pacific : age and growth in eastern North Pacific, 181-200

Combfish, longspine : pugheadedness in, 1G0-1G2

Components : of blood and serum from adult striped bass captured in Sacramento

River, 245-24G
Condor, California : plumage and molt as field study aids, 144-14S
Contribution : of two different sizes of silver salmon stocked in Lake Berryessa,

127-132
Cost: of two different sizes of silver salmon stock in Lake Berryessa, 127-132
Deer: Trapping with modified Clover deer trap, 242-244; trapping with Stewart

modified corral trap, 237-239
Distribution : of northern quahog in Long Beach, California, G8-81
Ecology : of ratfish in Gulf of California : 47-53
Elk, Rocky Mountain : status in Kern County, 1974, 239-241
Elkhorn Slough : site of study on life history of Trcstis nuttallii, 215-227
Evaluation : of fish species composition in limnetic areas of reservoirs with fish

trapping, 209-214
Fetus, extrauterine : in Steller sea lion. 233-234
Fish, poeciliid : newly introduced in California, 251-253
Fishes : collected from Richardson Bay, 1972-73, 104-lOG ; collected off the outer

coast of Baja California. 5G-59
Food : of Xeonujsis nicrcedis in the Sacramento-San Joaquin Estuary, 3.J-4G
Food habits : of leopard sharks, 95-103 ; of brown smoothhounds, 95-103
Frostfish, North Pacific: occurrence in Monterey Bay, 149-152
Growth : of Pacific bonito in eastern North Pacific, 181-200
Growth rate : of northern anchovy in southern California waters, 11G-12G ; of

northern quahog in Long Beach, California, G8-81 ; of Tilapia zillii, 54-5G
Growth rates : of two different sizes of silver salmon stocked in Lake Berryessa,

127-132
Gulf of California : site of study on the ecology of the ratfish, 47-53
Halibut, California : otter trawl cod-end escapement experiments for, 82-94
Kern County : status of Rocky Mountain elk, 1974, 239-241
Lake Berryessa : site of mortality and growth rate study of two different sizes of

stocked silver salmon, 127-132
Larvae : of diamond turbot, 26-34
Length composition : of northern anchovies in 1972-73 season California anchovy

reduction fishery, 133-143
Life history: of Tresiis nuttallii in Elkhorn Slough, 215-227
Little Kern River Basin : further record of Little Kern golden trout, 248-250
Long Beach, California : site of study on growth rate, distribution and population

density of northern quahog, G8-94
Measurement: of salmon using an old and unfamiliar method, 247
Method, new : of evaluating fish species composition in limnetic areas of reservoirs,

209-214
Method, old : of measuring salmon, 247
Minnow, fathead : occurrence in Oregon, 155-15G
Modification : of Clover deer trap, 242-244

Mollusks : range extension California, 152-155 ; size records in California, 152-155
Molt : of California condor as field study aid, 144-148

IMonterey Bay : occurrence of North Pacific frostfish, 14t>-152 ; occurrence of prow-
fish, 60-62 ; occurrence of parakeet auklet, 158 ; occurrence of pugheadedness in

longspine combfish, lGO-162
Mortality : of two different sizes of silver salmon stocked in Lake Berryessa, 127-132
Observations : on food habits of leopard shai-ks and brown smoothhounds, 9-5-103
Occurrence : of fathead minnow in Oregon, 155-1.50 ; of North Pacific fro&lifish in

Monterey Bay, 149-1.52 ; of parakeet auklet at Monterey Bay, 158 ; of prowfish in

Monterey Bay, 60-62 ; of yellow snake eel off southern California, 157-158
Otoliths: used as a means to calculate growth rate of northern anchovv in southern

California waters, 116-126
Otoliths, anomalous : from the northern anchovy, 23-5-236
Parasites : of fishes from Sacramento-San Joaquin Delta, 201-208
Parasites, external : of California inshore shark.s, 228-232
Plumage : of California condor as field study aid, 144-148
Polymorphism : in populations of Sccloponis occidcntalis in Santa Barbara County,

253^254

268 CALIFORNIA FISH AND GAME

Population density : of northern quahoj,' in Lon? Beach, California, G8-81
Population study : of black bear in northern California, 4-25

Populations: of Sceloporus occidcntaJis in Santa Barbara County exhil)itinp; poly-
morphism, 253-254
Prowfish : occurrence in ^Monterey Bay, G0-G2
Pugheadedness : in longspine combfish, lGO-162
Quahog, northern: growth rate, G8-94 ; distribution, 68-94; population density,

68-W
Range extension : for Terehra pedroana in California, 152-155
Range extension, depth : of the yellow snake eel, 157-158
Range extension, latitudinal : for yellow snake eel, 15G-157 ; for spotted snake eel,

150-157
Ratfish : note on ecology of, 47-53
Rays, bat : an unusual aggregation of, 159
Record, first: of Anthias gordensis, 111-112

Record, further : of Little Kern golden trout in Little Kern River Basin, 248-250
Records, size : for moUusks in California, 152-155
Reservoirs: evaluating fish species composition in limentic areas by fish trapping,

200-214
Reviews : A river never sleeps, 258 ; Fisherman's spring, 260 ; Fly casting with
Lefty Kreh, 256 ; Endemism in fishes of the Clear Lake region of central Cali-
fornia, 63 ; Freshwater ecology, 255 ; How to tie freshwater flies, 256 ; Marine
molluscan genera of western North America: An illustrated key. 259; Return to
the river, 257 ; Seashore life of Puget Sound, the Strait of Georgia, and the
San Juan Archipelago. 259-260 ; The blackbass in America and overseas, 260 ;
The carnivores, 255-256; The shore fishes of Hawaii, 258-259; The trout and
the stream, 257-258; Trout magic, 257; Western trout fly tying manual, 63;
Wilderness fishing for salmon and steelhead, 257
Richardson Bay : a list of fishes collected, 104-106
Sacramento River: site of study analyzing blood and serum of adult striped bass,

245-246
Sacramento-San Joaquin Delta : site of study on fish parasites, 201-208
Sacramento-San Joaquin Estuary : site of study on food habits of Xeomysis mercedis,

35-46
Salmon : an old and unfamiliar method of measuring. 247
Salmon, silver: mortality rates, 127-132; growth rates of two different sizes, 127-

132 ; cost of two different sizes, 127-132
San Francisco Bay : changes in species composition of sharks, 100-111
Sea lion, Steller, extrauterine fetus in, 233-234

Sharks: changes in species composition in south San Francisco Bay, 106-111
Sharks, brown smoothhound : food habits, 95-103
Sharks, inshore : external parasites collected from, 228-232
Sharks, leopard : food bal)its, 95-103
Snake eel, yellow : depth range extension, 157-158 ; latitudinal range extension,

150-157; occurrence off southern California, 157-158
Snake eel, spotted : latitudinal range extension, 156-157

Species composition : changes in shark species composition in south San Francisco
Bay, 106-111; of fish in limnetic areas of reservoirs as determined by fish
trapping, 209-214
Status : of Rocky Mountain elk in Kern County, 1974, 239-241
Statu.s, breeding : of tricolored blackbird, 1969-1972, 166-180
Study aids : used in California condor identification, 144-148
Trap, corral: Stewart modified type used in trapping deer, 237-239
Trap, deer: modification of Clover deer trap, 242-244
Trapping: a new method of evaluating fish species composition in limnetic areas of

reservoirs, 209-214
Trout, golden : further record of Little Kern golden trout in Little Kern River

Basin, 248-250
Turbot, diamond : larvae of, 26-34

A88038— 800 6-75 4,500 LDA

FISH AND GAME COAAMISSION
NOTICE OF MEETINGS

Notice is hereby given that the Fish and Game Commission shall meet on
October 3, 1975 at 9:00 a.m. in Room 1138, New State Building, 107 South
Broadway, Los Angeles, California, to receive recommendations from its own
officers and employees, from the department and other public agencies, from
organizations of private citizens, and from any interested groups as to what,
if any, regulations should be made relating to fish, amphibia and reptiles, or
any species or subspecies thereof.

Notice is hereby given that the Fish and Game Commission shall meet on
November 7, 1975 at 9:00 a.m. in the Auditorium of the San Diego Gas and
Electric Company, 101 Ash Street, San Diego, California, for public discus-
sion of and presentation of objections to, the proposals presented to the
commission on October 3, 1975, and after considering such discussion and
objections, the commission, at this meeting, shall announce the regulations
which it proposes to make relating to fish, amphibia and reptiles.

Notice is hereby given that the Fish and Game Commission shall meet on
December 5, 1975 at 9:00 a.m. in the Auditorium, Resources Building, 1416
Ninth Street, Sacramento, California, to hear and consider any objections
to its determinations or proposed orders in relation to fish, amphibia and
reptiles or any species or subspecies thereof for the 1976 sport fishing sea-
son; such determinations and orders resulting from the hearings held on
October 3, 1975 and November 7, 1975.

FISH AND GAME COAAMISSION

Leslie F. Edgerton
Executive Secrefary

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